diff --git a/apps/web/src/apps/auth/index.tsx b/apps/web/src/apps/auth/index.tsx
index 4eb4320..63edda4 100644
--- a/apps/web/src/apps/auth/index.tsx
+++ b/apps/web/src/apps/auth/index.tsx
@@ -1,14 +1,17 @@
 import { lazy } from 'react';
 import { Navigate, Route, Routes } from 'react-router-dom';
+import { AuthPageGuard } from '../../core/lib/auth-guard';
 
 const LoginPage = lazy(() => import('./login'));
 
 export default function AuthModule() {
   return (
-    <Routes>
-      <Route path="/login" element={<LoginPage />} />
-      <Route path="/" element={<Navigate to="/auth/login" replace={true} />} />
-      <Route path="*" element={<Navigate to={'/404'} replace={true} />} />
-    </Routes>
+    <AuthPageGuard>
+      <Routes>
+        <Route path="/login" element={<LoginPage />} />
+        <Route path="/" element={<Navigate to="/auth/login" replace={true} />} />
+        <Route path="*" element={<Navigate to={'/404'} replace={true} />} />
+      </Routes>
+    </AuthPageGuard>
   );
 }
diff --git a/apps/web/src/apps/main/index.tsx b/apps/web/src/apps/main/index.tsx
index 43a0893..dd55074 100644
--- a/apps/web/src/apps/main/index.tsx
+++ b/apps/web/src/apps/main/index.tsx
@@ -1,6 +1,7 @@
 import { lazy } from 'react';
 import { Navigate, Route, Routes } from 'react-router-dom';
 import ModuleLayout from './layouts/module.layout';
+import { GlobalCredentialChecker } from '../../core/lib/auth-guard';
 
 const ExampleModule = lazy(() => import('./modules/example'));
 const SystemSetting = lazy(() => import('./modules/system/setting'));
@@ -9,15 +10,17 @@ const SystemNotification = lazy(() => import('./modules/system/notification'));
 
 export default function AppModule() {
   return (
-    <ModuleLayout>
-      <Routes>
-        <Route path="/example/*" element={<ExampleModule />} />
-        <Route path="/system/setting" element={<SystemSetting />} />
-        <Route path="/system/information" element={<SystemInformation />} />
-        <Route path="/system/notifications" element={<SystemNotification />} />
-        <Route path="/" element={<Navigate to="/app/example/full-page" replace={true} />} />
-        <Route path="*" element={<Navigate to={'/404'} replace={true} />} />
-      </Routes>
-    </ModuleLayout>
+    <GlobalCredentialChecker>
+      <ModuleLayout>
+        <Routes>
+          <Route path="/example/*" element={<ExampleModule />} />
+          <Route path="/system/setting" element={<SystemSetting />} />
+          <Route path="/system/information" element={<SystemInformation />} />
+          <Route path="/system/notifications" element={<SystemNotification />} />
+          <Route path="/" element={<Navigate to="/app/example/full-page" replace={true} />} />
+          <Route path="*" element={<Navigate to={'/404'} replace={true} />} />
+        </Routes>
+      </ModuleLayout>
+    </GlobalCredentialChecker>
   );
 }
diff --git a/apps/web/src/core/lib/auth-guard.tsx b/apps/web/src/core/lib/auth-guard.tsx
new file mode 100644
index 0000000..7e4078e
--- /dev/null
+++ b/apps/web/src/core/lib/auth-guard.tsx
@@ -0,0 +1,92 @@
+import { useEffect, useState, ReactNode } from 'react';
+import { useNavigate } from 'react-router-dom';
+import { appDatabase, AppDatabaseKey } from '../storage/local';
+import { terminateAuthSession } from './auth.helper';
+
+/**
+ * Basic JWT decoder to check expiration.
+ */
+function isTokenExpired(token: string): boolean {
+  try {
+    const payload = JSON.parse(atob(token.split('.')[1]));
+    if (payload.exp) {
+      return payload.exp * 1000 < Date.now();
+    }
+    return false; // If no exp, assume valid
+  } catch (e) {
+    return true; // Invalid token format -> treat as expired
+  }
+}
+
+/**
+ * For Auth Page (Login/Register).
+ * - If valid token exists -> Redirect to main application.
+ * - If expired token exists -> Clear session, stay on auth page.
+ */
+export function AuthPageGuard({ children }: { children: ReactNode }) {
+  const navigate = useNavigate();
+  const [isChecking, setIsChecking] = useState(true);
+
+  useEffect(() => {
+    async function checkCredential() {
+      try {
+        const token = await appDatabase.getItem<string>(AppDatabaseKey.ACCESS_TOKEN);
+        if (token) {
+          if (!isTokenExpired(token)) {
+            // Valid token exists, redirect to dashboard/main app
+            navigate('/app', { replace: true });
+            return;
+          } else {
+            // Token exists but is expired. Terminate session without redirecting (we are already in Auth).
+            await terminateAuthSession({ preserveRedirect: false });
+          }
+        }
+        setIsChecking(false);
+      } catch (error) {
+        console.error('Failed to check credentials in AuthPageGuard:', error);
+        setIsChecking(false);
+      }
+    }
+
+    checkCredential();
+  }, [navigate]);
+
+  if (isChecking) return null;
+
+  return <>{children}</>;
+}
+
+/**
+ * For Root/Main App.
+ * - Monitors token status.
+ * - If expired -> Immediately terminate session and redirect to login.
+ */
+export function GlobalCredentialChecker({ children }: { children: ReactNode }) {
+  useEffect(() => {
+    let intervalId: any;
+
+    async function checkCredential() {
+      try {
+        const token = await appDatabase.getItem<string>(AppDatabaseKey.ACCESS_TOKEN);
+        if (!token || isTokenExpired(token)) {
+          // Token is missing or expired -> clear session and redirect to login
+          await terminateAuthSession({ preserveRedirect: true });
+        }
+      } catch (error) {
+        console.error('Failed to check credentials in GlobalCredentialChecker:', error);
+        await terminateAuthSession({ preserveRedirect: true });
+      }
+    }
+
+    // Immediate check on mount
+    checkCredential();
+
+    // Periodic check every 1 minute
+    // eslint-disable-next-line prefer-const
+    intervalId = setInterval(checkCredential, 60000);
+
+    return () => clearInterval(intervalId);
+  }, []);
+
+  return <>{children}</>;
+}