diff --git a/app/[lang]/page.tsx b/app/[lang]/page.tsx
index 2a6049f..9d1e95a 100644
--- a/app/[lang]/page.tsx
+++ b/app/[lang]/page.tsx
@@ -4,7 +4,6 @@ import { Suspense, useCallback, useEffect, useRef, useState } from "react"
 import { DrawIoEmbed } from "react-drawio"
 import type { ImperativePanelHandle } from "react-resizable-panels"
 import ChatPanel from "@/components/chat-panel"
-import { STORAGE_CLOSE_PROTECTION_KEY } from "@/components/settings-dialog"
 import {
     ResizableHandle,
     ResizablePanel,
@@ -29,7 +28,6 @@ export default function Home() {
     const [darkMode, setDarkMode] = useState(false)
     const [isLoaded, setIsLoaded] = useState(false)
     const [isDrawioReady, setIsDrawioReady] = useState(false)
-    const [closeProtection, setCloseProtection] = useState(false)
 
     const chatPanelRef = useRef<ImperativePanelHandle>(null)
     const isMobileRef = useRef(false)
@@ -66,13 +64,6 @@ export default function Home() {
             document.documentElement.classList.toggle("dark", prefersDark)
         }
 
-        const savedCloseProtection = localStorage.getItem(
-            STORAGE_CLOSE_PROTECTION_KEY,
-        )
-        if (savedCloseProtection === "true") {
-            setCloseProtection(true)
-        }
-
         setIsLoaded(true)
     }, [pathname, router])
 
@@ -146,20 +137,6 @@ export default function Home() {
         return () => window.removeEventListener("keydown", handleKeyDown)
     }, [])
 
-    // Show confirmation dialog when user tries to leave the page
-    useEffect(() => {
-        if (!closeProtection) return
-
-        const handleBeforeUnload = (event: BeforeUnloadEvent) => {
-            event.preventDefault()
-            return ""
-        }
-
-        window.addEventListener("beforeunload", handleBeforeUnload)
-        return () =>
-            window.removeEventListener("beforeunload", handleBeforeUnload)
-    }, [closeProtection])
-
     return (
         <div className="h-screen bg-background relative overflow-hidden">
             <ResizablePanelGroup
@@ -243,7 +220,6 @@ export default function Home() {
                                 darkMode={darkMode}
                                 onToggleDarkMode={handleDarkModeChange}
                                 isMobile={isMobile}
-                                onCloseProtectionChange={setCloseProtection}
                             />
                         </Suspense>
                     </div>
diff --git a/components/chat-panel.tsx b/components/chat-panel.tsx
index 0dda333..40f4edb 100644
--- a/components/chat-panel.tsx
+++ b/components/chat-panel.tsx
@@ -70,7 +70,6 @@ interface ChatPanelProps {
     darkMode: boolean
     onToggleDarkMode: () => void
     isMobile?: boolean
-    onCloseProtectionChange?: (enabled: boolean) => void
 }
 
 // Constants for tool states
@@ -111,7 +110,6 @@ export default function ChatPanel({
     darkMode,
     onToggleDarkMode,
     isMobile = false,
-    onCloseProtectionChange,
 }: ChatPanelProps) {
     const {
         loadDiagram: onDisplayChart,
@@ -1296,7 +1294,6 @@ export default function ChatPanel({
             <SettingsDialog
                 open={showSettingsDialog}
                 onOpenChange={setShowSettingsDialog}
-                onCloseProtectionChange={onCloseProtectionChange}
                 drawioUi={drawioUi}
                 onToggleDrawioUi={onToggleDrawioUi}
                 darkMode={darkMode}
diff --git a/components/settings-dialog.tsx b/components/settings-dialog.tsx
index 5882675..32cc4fb 100644
--- a/components/settings-dialog.tsx
+++ b/components/settings-dialog.tsx
@@ -61,7 +61,6 @@ const LANGUAGE_LABELS: Record<Locale, string> = {
 interface SettingsDialogProps {
     open: boolean
     onOpenChange: (open: boolean) => void
-    onCloseProtectionChange?: (enabled: boolean) => void
     drawioUi: "min" | "sketch"
     onToggleDrawioUi: () => void
     darkMode: boolean
@@ -71,7 +70,6 @@ interface SettingsDialogProps {
 }
 
 export const STORAGE_ACCESS_CODE_KEY = "next-ai-draw-io-access-code"
-export const STORAGE_CLOSE_PROTECTION_KEY = "next-ai-draw-io-close-protection"
 const STORAGE_ACCESS_CODE_REQUIRED_KEY = "next-ai-draw-io-access-code-required"
 
 function getStoredAccessCodeRequired(): boolean | null {
@@ -84,7 +82,6 @@ function getStoredAccessCodeRequired(): boolean | null {
 function SettingsContent({
     open,
     onOpenChange,
-    onCloseProtectionChange,
     drawioUi,
     onToggleDrawioUi,
     darkMode,
@@ -97,7 +94,6 @@ function SettingsContent({
     const pathname = usePathname() || "/"
     const search = useSearchParams()
     const [accessCode, setAccessCode] = useState("")
-    const [closeProtection, setCloseProtection] = useState(true)
     const [isVerifying, setIsVerifying] = useState(false)
     const [error, setError] = useState("")
     const [accessCodeRequired, setAccessCodeRequired] = useState(
@@ -151,12 +147,6 @@ function SettingsContent({
                 localStorage.getItem(STORAGE_ACCESS_CODE_KEY) || ""
             setAccessCode(storedCode)
 
-            const storedCloseProtection = localStorage.getItem(
-                STORAGE_CLOSE_PROTECTION_KEY,
-            )
-            // Default to true if not set
-            setCloseProtection(storedCloseProtection !== "false")
-
             const storedSendShortcut = localStorage.getItem(
                 STORAGE_KEYS.sendShortcut,
             )
@@ -394,25 +384,6 @@ function SettingsContent({
                         </Button>
                     </SettingItem>
 
-                    {/* Close Protection */}
-                    <SettingItem
-                        label={dict.settings.closeProtection}
-                        description={dict.settings.closeProtectionDescription}
-                    >
-                        <Switch
-                            id="close-protection"
-                            checked={closeProtection}
-                            onCheckedChange={(checked) => {
-                                setCloseProtection(checked)
-                                localStorage.setItem(
-                                    STORAGE_CLOSE_PROTECTION_KEY,
-                                    checked.toString(),
-                                )
-                                onCloseProtectionChange?.(checked)
-                            }}
-                        />
-                    </SettingItem>
-
                     {/* Diagram Style */}
                     <SettingItem
                         label={dict.settings.diagramStyle}
diff --git a/lib/i18n/dictionaries/en.json b/lib/i18n/dictionaries/en.json
index 4e43a39..745c9bb 100644
--- a/lib/i18n/dictionaries/en.json
+++ b/lib/i18n/dictionaries/en.json
@@ -100,8 +100,6 @@
         "switchTo": "Switch to",
         "minimal": "Minimal",
         "sketch": "Sketch",
-        "closeProtection": "Close Protection",
-        "closeProtectionDescription": "Show confirmation when leaving the page.",
         "diagramStyle": "Diagram Style",
         "diagramStyleDescription": "Toggle between minimal and styled diagram output.",
         "sendShortcut": "Send Shortcut",
diff --git a/lib/i18n/dictionaries/ja.json b/lib/i18n/dictionaries/ja.json
index bfafb62..9f6464d 100644
--- a/lib/i18n/dictionaries/ja.json
+++ b/lib/i18n/dictionaries/ja.json
@@ -100,8 +100,6 @@
         "switchTo": "切り替え",
         "minimal": "ミニマル",
         "sketch": "スケッチ",
-        "closeProtection": "ページ離脱確認",
-        "closeProtectionDescription": "ページを離れる際に確認を表示します。",
         "diagramStyle": "ダイアグラムスタイル",
         "diagramStyleDescription": "ミニマルとスタイル付きの出力を切り替えます。",
         "sendShortcut": "送信ショートカット",
diff --git a/lib/i18n/dictionaries/zh.json b/lib/i18n/dictionaries/zh.json
index ce431c8..5fd6df0 100644
--- a/lib/i18n/dictionaries/zh.json
+++ b/lib/i18n/dictionaries/zh.json
@@ -100,8 +100,6 @@
         "switchTo": "切换到",
         "minimal": "简约",
         "sketch": "草图",
-        "closeProtection": "关闭确认",
-        "closeProtectionDescription": "离开页面时显示确认。",
         "diagramStyle": "图表样式",
         "diagramStyleDescription": "切换简约与精致图表输出模式。",
         "sendShortcut": "发送快捷键",
diff --git a/lib/storage.ts b/lib/storage.ts
index 623ccb4..57974e9 100644
--- a/lib/storage.ts
+++ b/lib/storage.ts
@@ -12,7 +12,6 @@ export const STORAGE_KEYS = {
 
     // Settings
     accessCode: "next-ai-draw-io-access-code",
-    closeProtection: "next-ai-draw-io-close-protection",
     accessCodeRequired: "next-ai-draw-io-access-code-required",
     aiProvider: "next-ai-draw-io-ai-provider",
     aiBaseUrl: "next-ai-draw-io-ai-base-url",