diff --git a/src/background.ts b/src/background.ts
index 8db9e8a3..5cf60c67 100644
--- a/src/background.ts
+++ b/src/background.ts
@@ -1,38 +1,23 @@
 'use strict'
 
-import * as path from 'path'
 import { pick } from 'lodash'
 import {
     app,
     ipcMain,
     protocol,
-    shell,
-    BrowserWindow,
-    Menu,
-} from 'electron'
-// Electron types
-import {
-    App,
-    BrowserWindowConstructorOptions,
     Event,
-    MenuItemConstructorOptions,
 } from 'electron'
 
 import ContextMenu from 'electron-context-menu'
-import {
-    createProtocol,
-    installVueDevtools
-} from 'vue-cli-plugin-electron-builder/lib'
-// tslint:disable-next-line:no-var-requires
-const localShortcut = require('electron-localshortcut')
+
+import Application from './main/Application'
+import ApplicationMenu from "./main/ApplicationMenu";
 
 export type PackageJson = typeof import('../package.json');
-import { bugs, homepage } from '../package.json'
+import { homepage } from '../package.json'
 import TheDeskInfo from '../info.json'
 export type TheDeskInfoObject = typeof TheDeskInfo;
 
-declare const __static: string;
-
 ipcMain.on('thedesk-info', (event: Event) => {
     event.returnValue = Object.assign({
         productName: app.getName(),
@@ -59,275 +44,7 @@ if (isDevelopment) {
 
 protocol.registerStandardSchemes(['app'], { secure: true })
 
-interface CreateWindowOptions {
-    windowName: string
-    loadPath: string
-    windowOptions?: BrowserWindowConstructorOptions
-    singleton?: boolean
-    lastAction?: (win: BrowserWindow) => void
-    openDevTools?: boolean
-}
-
-class Application {
-    public app: App;
-    public windows: { [key: string]: BrowserWindow } = {};
-
-    constructor(app: App) {
-        this.app = app;
-        ContextMenu()
-        this.app.on('window-all-closed', () => this.onWindowAllClosed())
-        this.app.on('ready', () => this.onReady());
-        this.app.on('activate', () => this.onActivated());
-    }
-
-    private onWindowAllClosed() {
-        if (process.platform !== 'darwin') {
-            this.app.quit()
-        }
-    }
-
-    private async onReady() {
-        if (isDevelopment && !process.env.IS_TEST) {
-            // Install Vue Devtools
-            try {
-                await installVueDevtools()
-            } catch (e) {
-                //console.error('Vue Devtools failed to install:', e.toString())
-            }
-        }
-        if (!process.env.WEBPACK_DEV_SERVER_URL) createProtocol('app')
-        this.openMainWindow()
-    }
-
-    private onActivated() {
-        if (typeof this.windows.main === 'undefined') {
-            this.openMainWindow()
-        }
-    }
-
-    public openMainWindow() {
-        const opts: CreateWindowOptions = {
-            windowName: 'main',
-            loadPath: 'index.html',
-            windowOptions: {
-                icon: path.join(__static, 'icon.png'),
-                width: 800,
-                height: 600,
-                autoHideMenuBar: true,
-            },
-            singleton: true,
-            lastAction: (win) => {
-                localShortcut.register(win, 'F5', () => this.windows.main.reload())
-            },
-            openDevTools: !process.env.IS_TEST
-        }
-        this.createWindow(opts)
-    }
-
-    public openAboutWindow() {
-        const opts: CreateWindowOptions = {
-            windowName: 'about',
-            loadPath: 'about.html',
-            windowOptions: {
-                width: 296,
-                height: 432,
-                resizable: false,
-                minimizable: false,
-                maximizable: false,
-                fullscreenable: false,
-                autoHideMenuBar: true,
-                titleBarStyle: 'hiddenInset',
-            },
-            singleton: true,
-            lastAction: (win) => {
-                win.setMenuBarVisibility(false)
-                win.webContents.on('before-input-event', (event, input) => {
-                    if (typeof this.windows.about !== 'undefined')
-                        this.windows.about.webContents.setIgnoreMenuShortcuts((input.meta || input.control) && input.key !== "R" || input.key === "F5")
-                })
-                localShortcut.register(win, 'Esc', () => this.windows.about.destroy())
-            },
-            openDevTools: !process.env.IS_TEST
-        }
-        this.createWindow(opts)
-    }
-
-    private async createWindow(options: CreateWindowOptions) {
-        if (typeof this.windows[options.windowName] !== 'undefined') {
-            this.windows[options.windowName].show()
-            return
-        }
-        let win = new BrowserWindow(options.windowOptions)
-        win.hide()
-        win.webContents.on('did-finish-load', () => {
-            this.windows[options.windowName].show()
-        })
-
-        win.on('closed', () => {
-            delete this.windows[options.windowName]
-        })
-
-        let openUrl = (event: Event, url: string) => {
-            if (isDevelopment && url === process.env.WEBPACK_DEV_SERVER_URL + options.loadPath) {
-                return
-            }
-            event.preventDefault()
-            shell.openExternal(url, {
-                activate: false
-            }, (err) => {
-                //if (err) console.log(err)
-            })
-        }
-        win.webContents.on('will-navigate', openUrl)
-        win.webContents.on('new-window', openUrl)
-
-        if (process.env.WEBPACK_DEV_SERVER_URL) {
-            // `electron:serve`で起動した時の読み込み
-            win.loadURL(process.env.WEBPACK_DEV_SERVER_URL + options.loadPath)
-        } else {
-            // ビルドしたアプリでの読み込み
-            win.loadURL(`app://./${options.loadPath}`)
-        }
-
-        if (isDevelopment && options.openDevTools) win.webContents.openDevTools()
-
-        if (typeof options.lastAction === 'function') options.lastAction(win)
-
-        this.windows[options.windowName] = win
-    }
-}
-
-class ApplicationMenu {
-    private app: Application;
-
-    // Mac only menu. prefix `macOnly`. First Item always separator
-    private macOnlyAppMenu: MenuItemConstructorOptions[] = [
-        { type: 'separator' },
-        { role: 'services' },
-        { type: 'separator' },
-        { role: 'hide' },
-        { role: 'hideOthers' },
-        { role: 'unhide' },
-    ];
-    private macOnlyEditMenu: MenuItemConstructorOptions[] = [
-        { type: 'separator' },
-        {
-            label: 'Speech',
-            submenu: [
-                { role: 'startspeaking' },
-                { role: 'stopspeaking' },
-            ]
-        }
-    ];
-
-    private get aboutMenuItem(): MenuItemConstructorOptions {
-        return {
-            label: process.platform !== 'darwin' ? 'About' : `About ${this.app.app.getName()}`,
-            click: () => this.app.openAboutWindow(),
-        }
-    }
-
-    constructor(app: Application) {
-        this.app = app;
-    }
-
-    public setApplicationMenu() {
-        const menu = Menu.buildFromTemplate(this.buildTemplate(process.platform === 'darwin'))
-        Menu.setApplicationMenu(menu)
-    }
-
-    private buildTemplate(isMac: boolean): MenuItemConstructorOptions[] {
-        return [
-            this.AppMenu(isMac),
-            this.EditMenu(isMac),
-            this.ViewMenu(),
-            this.WindowMenu(isMac),
-            this.HelpMenu(),
-        ]
-    }
-
-    private AppMenu(isMac: boolean): MenuItemConstructorOptions {
-        let appMenu: MenuItemConstructorOptions[] = [
-            this.aboutMenuItem,
-            ...(isMac ? this.macOnlyAppMenu : []),
-            { type: 'separator' },
-            { role: 'quit' },
-        ]
-        return {
-            label: this.app.app.getName(),
-            submenu: appMenu,
-        }
-    }
-
-    private EditMenu(isMac: boolean): MenuItemConstructorOptions {
-        let editMenu: MenuItemConstructorOptions[] = [
-            { role: 'undo' },
-            { role: 'redo' },
-            { type: 'separator' },
-            { role: 'cut' },
-            { role: 'copy' },
-            { role: 'paste' },
-            { role: 'pasteandmatchstyle' },
-            { role: 'delete' },
-            { role: 'selectall' },
-            ...(isMac ? this.macOnlyEditMenu : []),
-        ]
-        return {
-            label: 'Edit',
-            submenu: editMenu,
-        }
-    }
-
-    private ViewMenu(): MenuItemConstructorOptions {
-        let viewMenu: MenuItemConstructorOptions[] = [
-            { role: 'reload' },
-            { role: 'forcereload' },
-            { role: 'toggledevtools' },
-            { type: 'separator' },
-            { role: 'togglefullscreen' },
-        ]
-        return {
-            label: 'View',
-            submenu: viewMenu
-        }
-    }
-
-    private WindowMenu(isMac: boolean): MenuItemConstructorOptions {
-        let windowMenu: MenuItemConstructorOptions[] = isMac ? [
-            { role: 'close' },
-            { role: 'minimize' },
-            { role: 'zoom' },
-            { type: 'separator' },
-            { role: 'front' },
-        ] : [
-                { role: 'minimize' },
-                { role: 'close' },
-            ]
-        return {
-            label: 'Window',
-            submenu: windowMenu,
-        }
-    }
-
-    private HelpMenu(): MenuItemConstructorOptions {
-        let helpMenu: MenuItemConstructorOptions[] = [
-            {
-                label: 'Report an issue',
-                click: () => shell.openExternal(`${bugs.url}/new`),
-            },
-            {
-                label: 'Learn More',
-                click: () => shell.openExternal(TheDeskInfo.documentURL),
-            }
-        ]
-        return {
-            label: 'Help',
-            submenu: helpMenu,
-        }
-    }
-}
-
-const TheDeskVueApp: Application = new Application(app)
-const MainMenu: ApplicationMenu = new ApplicationMenu(TheDeskVueApp)
-MainMenu.setApplicationMenu()
+ContextMenu()
 
+const TheDeskVueApp: Application = Application.shared
+TheDeskVueApp.setApplicationMenu(ApplicationMenu.buildTemplate())
\ No newline at end of file
diff --git a/src/main/Application.ts b/src/main/Application.ts
new file mode 100644
index 00000000..db613a7b
--- /dev/null
+++ b/src/main/Application.ts
@@ -0,0 +1,55 @@
+import {
+    app,
+    Menu,
+} from 'electron'
+import {
+    createProtocol,
+    installVueDevtools,
+} from 'vue-cli-plugin-electron-builder/lib'
+import Window from './Window'
+
+const isDevelopment = process.env.NODE_ENV !== 'production'
+
+export default class Application {
+    private static _instance: Application;
+
+    public static get shared() {
+        // Do you need arguments? Make it a regular static method instead.
+        return this._instance || (this._instance = new this());
+    }
+
+    private constructor() {
+        app.on('window-all-closed', () => this.onWindowAllClosed())
+        app.on('ready', () => this.onReady());
+        app.on('activate', () => this.onActivated());
+    }
+
+    public setApplicationMenu(menu: Menu) {
+        Menu.setApplicationMenu(menu)
+    }
+
+    private onWindowAllClosed() {
+        if (process.platform !== 'darwin') {
+            app.quit()
+        }
+    }
+
+    private async onReady() {
+        if (isDevelopment && !process.env.IS_TEST) {
+            // Install Vue Devtools
+            try {
+                await installVueDevtools()
+            } catch (e) {
+                //console.error('Vue Devtools failed to install:', e.toString())
+            }
+        }
+        if (!process.env.WEBPACK_DEV_SERVER_URL) createProtocol('app')
+        Window.Main()
+    }
+
+    private onActivated() {
+        if (!Window.single.has('main')) {
+            Window.Main()
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/ApplicationMenu.ts b/src/main/ApplicationMenu.ts
new file mode 100644
index 00000000..30da6f88
--- /dev/null
+++ b/src/main/ApplicationMenu.ts
@@ -0,0 +1,126 @@
+import {
+    app,
+    shell,
+    Menu,
+    MenuItemConstructorOptions
+} from 'electron';
+import Window from "./Window";
+import { bugs } from '../../package.json';
+import { documentURL } from '../../info.json';
+
+const isMac = process.platform === 'darwin'
+
+export default class ApplicationMenu {
+    // Mac only menu. prefix `macOnly`. First Item always separator
+    private static macOnlyAppMenu: MenuItemConstructorOptions[] = [
+        { type: 'separator' },
+        { role: 'services' },
+        { type: 'separator' },
+        { role: 'hide' },
+        { role: 'hideOthers' },
+        { role: 'unhide' },
+    ];
+    private static macOnlyEditMenu: MenuItemConstructorOptions[] = [
+        { type: 'separator' },
+        {
+            label: 'Speech',
+            submenu: [
+                { role: 'startspeaking' },
+                { role: 'stopspeaking' },
+            ]
+        }
+    ];
+    private static aboutMenuItem: MenuItemConstructorOptions = {
+        label: process.platform !== 'darwin' ? 'About' : `About ${app.getName()}`,
+        click: () => Window.About(),
+    }
+
+    public static get menuConstruct(): MenuItemConstructorOptions[] {
+        return [
+            this.AppMenu(isMac),
+            this.EditMenu(isMac),
+            this.ViewMenu(),
+            this.WindowMenu(isMac),
+            this.HelpMenu(),
+        ]
+    }
+
+    public static buildTemplate(): Menu {
+        return Menu.buildFromTemplate(this.menuConstruct);
+    }
+    private static AppMenu(isMac: boolean): MenuItemConstructorOptions {
+        let appMenu: MenuItemConstructorOptions[] = [
+            this.aboutMenuItem,
+            ...(isMac ? this.macOnlyAppMenu : []),
+            { type: 'separator' },
+            { role: 'quit' },
+        ];
+        return {
+            label: app.getName(),
+            submenu: appMenu,
+        };
+    }
+    private static EditMenu(isMac: boolean): MenuItemConstructorOptions {
+        let editMenu: MenuItemConstructorOptions[] = [
+            { role: 'undo' },
+            { role: 'redo' },
+            { type: 'separator' },
+            { role: 'cut' },
+            { role: 'copy' },
+            { role: 'paste' },
+            { role: 'pasteandmatchstyle' },
+            { role: 'delete' },
+            { role: 'selectall' },
+            ...(isMac ? this.macOnlyEditMenu : []),
+        ];
+        return {
+            label: 'Edit',
+            submenu: editMenu,
+        };
+    }
+    private static ViewMenu(): MenuItemConstructorOptions {
+        let viewMenu: MenuItemConstructorOptions[] = [
+            { role: 'reload' },
+            { role: 'forcereload' },
+            { role: 'toggledevtools' },
+            { type: 'separator' },
+            { role: 'togglefullscreen' },
+        ];
+        return {
+            label: 'View',
+            submenu: viewMenu
+        };
+    }
+    private static WindowMenu(isMac: boolean): MenuItemConstructorOptions {
+        let windowMenu: MenuItemConstructorOptions[] = isMac ? [
+            { role: 'close' },
+            { role: 'minimize' },
+            { role: 'zoom' },
+            { type: 'separator' },
+            { role: 'front' },
+        ] : [
+                { role: 'minimize' },
+                { role: 'close' },
+            ];
+        return {
+            label: 'Window',
+            submenu: windowMenu,
+        };
+    }
+    private static HelpMenu(): MenuItemConstructorOptions {
+        let helpMenu: MenuItemConstructorOptions[] = [
+            {
+                label: 'Report an issue',
+                click: () => shell.openExternal(`${bugs.url}/new`),
+            },
+            {
+                label: 'Learn More',
+                click: () => shell.openExternal(documentURL),
+            }
+        ];
+        return {
+            label: 'Help',
+            submenu: helpMenu,
+        };
+    }
+}
diff --git a/src/main/Window.ts b/src/main/Window.ts
new file mode 100644
index 00000000..b06f09f1
--- /dev/null
+++ b/src/main/Window.ts
@@ -0,0 +1,119 @@
+import { join } from 'path'
+
+import {
+    shell,
+    BrowserWindow,
+    BrowserWindowConstructorOptions,
+    Event,
+    Input,
+    app,
+} from 'electron'
+import { register as shortcutRegister } from 'electron-localshortcut'
+
+declare const __static: string;
+const isDevelopment = process.env.NODE_ENV !== 'production'
+
+export interface CreateWindowOptions {
+    windowName: string
+    loadPath: string
+    windowOptions?: BrowserWindowConstructorOptions
+    singleton?: boolean
+    lastAction?: (win: BrowserWindow) => void
+    openDevTools?: boolean
+}
+
+export default class Window {
+    public static single: Map<string, BrowserWindow> = new Map()
+    public static list: BrowserWindow[]
+
+    public static Main() {
+        const opts: CreateWindowOptions = {
+            windowName: 'main',
+            loadPath: 'index.html',
+            windowOptions: {
+                icon: join(__static, 'icon.png'),
+                width: 800,
+                height: 600,
+                autoHideMenuBar: true,
+            },
+            singleton: true,
+            lastAction: (win) => {
+                shortcutRegister(win, 'F5', () => this.single.get('main')!.reload())
+            },
+            openDevTools: !process.env.IS_TEST
+        }
+
+        this.createWindow(opts)
+    }
+
+    public static About() {
+        const opts: CreateWindowOptions = {
+            windowName: 'about',
+            loadPath: 'about.html',
+            windowOptions: {
+                width: 296,
+                height: 432,
+                resizable: false,
+                minimizable: false,
+                maximizable: false,
+                fullscreenable: false,
+                autoHideMenuBar: true,
+                titleBarStyle: 'hiddenInset',
+            },
+            singleton: true,
+            lastAction: (win) => {
+                win.setMenuBarVisibility(false)
+                win.webContents.on('before-input-event', (event: Event, input: Input) => {
+                    this.single.get('about')!.webContents.setIgnoreMenuShortcuts((process.platform === 'darwin' ? input.meta : input.control) && input.key === "r")
+                })
+                shortcutRegister(win, 'Esc', () => this.single.get('about')!.destroy())
+            },
+            openDevTools: !process.env.IS_TEST
+        }
+        this.createWindow(opts)
+    }
+
+    public static async createWindow(options: CreateWindowOptions) {
+        if (options.singleton && this.single.has(options.windowName)) {
+            this.single.get(options.windowName)!.show()
+            return
+        }
+        let win = new BrowserWindow(options.windowOptions)
+        win.hide()
+        win.webContents.on('did-finish-load', () => {
+            win.show()
+        })
+
+        win.on('closed', () => {
+            this.single.delete(options.windowName)
+        })
+
+        let openUrl = (event: Event, url: string) => {
+            if (isDevelopment && url === process.env.WEBPACK_DEV_SERVER_URL + options.loadPath) {
+                return
+            }
+            event.preventDefault()
+            shell.openExternal(url, {
+                activate: false
+            }, (err) => {
+                //if (err) console.log(err)
+            })
+        }
+        win.webContents.on('will-navigate', openUrl)
+        win.webContents.on('new-window', openUrl)
+
+        if (process.env.WEBPACK_DEV_SERVER_URL) {
+            // `electron:serve`で起動した時の読み込み
+            win.loadURL(process.env.WEBPACK_DEV_SERVER_URL + options.loadPath)
+        } else {
+            // ビルドしたアプリでの読み込み
+            win.loadURL(`app://./${options.loadPath}`)
+        }
+
+        if (isDevelopment && options.openDevTools) win.webContents.openDevTools()
+
+        if (typeof options.lastAction === 'function') options.lastAction(win)
+
+        this.single.set(options.windowName, win)
+    }
+}
\ No newline at end of file