diff --git a/frontend/src/hooks/useAppUpdateManager.test.tsx b/frontend/src/hooks/useAppUpdateManager.test.tsx
index 6146a5da..a08927ae 100644
--- a/frontend/src/hooks/useAppUpdateManager.test.tsx
+++ b/frontend/src/hooks/useAppUpdateManager.test.tsx
@@ -157,9 +157,46 @@ describe('useAppUpdateManager', () => {
 
     expect(backendApp.DownloadUpdate).toHaveBeenCalledTimes(1);
     expect(backendApp.OpenDownloadedUpdateDirectory).not.toHaveBeenCalled();
+    expect(backendApp.InstallUpdateAndRestart).not.toHaveBeenCalled();
     expect(hook?.lastUpdateInfo?.downloaded).toBe(true);
   });
 
+  it('auto-installs a macOS update immediately after download when the backend reports auto relaunch support', async () => {
+    backendApp.CheckForUpdates.mockResolvedValue({
+      success: true,
+      data: {
+        hasUpdate: true,
+        currentVersion: '0.8.1',
+        latestVersion: '0.8.2',
+        downloaded: false,
+        assetSize: 2048,
+      },
+    });
+    backendApp.DownloadUpdate.mockResolvedValue({
+      success: true,
+      data: {
+        platform: 'darwin',
+        autoRelaunch: true,
+        downloadPath: '/Users/test/Desktop/GoNavi-0.8.2/GoNavi-0.8.2-MacOS-Arm64.dmg',
+      },
+    });
+    backendApp.InstallUpdateAndRestart.mockResolvedValue({ success: true });
+
+    renderHook();
+
+    await act(async () => {
+      await hook?.checkForUpdates(false);
+    });
+
+    await act(async () => {
+      await hook?.downloadUpdate(hook?.lastUpdateInfo!, false);
+    });
+
+    expect(backendApp.DownloadUpdate).toHaveBeenCalledTimes(1);
+    expect(backendApp.InstallUpdateAndRestart).toHaveBeenCalledTimes(1);
+    expect(backendApp.OpenDownloadedUpdateDirectory).not.toHaveBeenCalled();
+  });
+
   it('switches update channel and re-checks against the selected channel', async () => {
     backendApp.SetUpdateChannel.mockResolvedValue({ success: true, data: { channel: 'dev' } });
     backendApp.CheckForUpdates.mockResolvedValue({
diff --git a/frontend/src/hooks/useAppUpdateManager.ts b/frontend/src/hooks/useAppUpdateManager.ts
index 6880d498..f6be441d 100644
--- a/frontend/src/hooks/useAppUpdateManager.ts
+++ b/frontend/src/hooks/useAppUpdateManager.ts
@@ -63,6 +63,11 @@ const buildUpdateKey = (info: Pick<UpdateInfo, 'channel' | 'latestVersion'> | nu
     ? `${normalizeUpdateChannel(info.channel)}:${String(info.latestVersion || '').trim()}`
     : '';
 
+const shouldAutoInstallDownloadedUpdate = (resultData: UpdateDownloadResultData | null | undefined): boolean => {
+  const platform = String(resultData?.platform || '').trim().toLowerCase();
+  return platform === 'darwin' && resultData?.autoRelaunch !== false;
+};
+
 export const useAppUpdateManager = ({
   runtimeBuildType,
   t,
@@ -192,6 +197,21 @@ export const useAppUpdateManager = ({
         void message.success({ content: t('app.about.message.download_completed'), duration: 2 });
       }
       setAboutUpdateStatus(formatAboutUpdateStatus({ ...info, channel: normalizeUpdateChannel(info.channel), downloaded: true }));
+
+      if (shouldAutoInstallDownloadedUpdate(resultData)) {
+        let installRes: any = null;
+        try {
+          installRes = await (window as any).go?.app?.App?.InstallUpdateAndRestart?.();
+        } catch (error: any) {
+          installRes = { success: false, message: error?.message || t('common.unknown') };
+        }
+        if (!installRes?.success) {
+          void message.error(t('app.about.message.install_failed_with_error', { error: installRes?.message || t('common.unknown') }));
+          return;
+        }
+        updateInstallTriggeredVersionRef.current = targetKey || null;
+        setUpdateDownloadProgress((prev) => ({ ...prev, open: false }));
+      }
     } else {
       setUpdateDownloadProgress((prev) => ({
         ...prev,