diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 3c450c434ed58604aed9218429dcced4d64cb0ae..ae7cb65642ed7389ad8141c7acd8e2cf599c474e 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -9,6 +9,7 @@
     <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
     <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
     <uses-permission android:name="android.permission.READ_MEDIA_VISUAL_USER_SELECTED" />
+    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
 
     <application
         android:name=".AwApp"
diff --git a/app/src/main/java/jp/atled/agileworks/AwApp.kt b/app/src/main/java/jp/atled/agileworks/AwApp.kt
index 7e3fdb14e9b621528eb5c21de08aa1c82bb47614..deb1ce4304abffbde77094a7311ae72707b42be4 100644
--- a/app/src/main/java/jp/atled/agileworks/AwApp.kt
+++ b/app/src/main/java/jp/atled/agileworks/AwApp.kt
@@ -4,6 +4,7 @@ import android.app.Application
 import jp.atled.agileworks.model.CertRepository
 import jp.atled.agileworks.model.LoginRepository
 import jp.atled.agileworks.model.api.ApiClient
+import jp.atled.agileworks.widget.NetworkStateMonitor
 import java.util.concurrent.Executors
 
 class AwApp : Application() {
@@ -12,6 +13,8 @@ class AwApp : Application() {
 
     private val executor = Executors.newFixedThreadPool(4)
 
+    private lateinit var networkStateMonitor: NetworkStateMonitor
+
     override fun onCreate() {
         super.onCreate()
         instance = this
@@ -20,6 +23,15 @@ class AwApp : Application() {
                 ApiClient.reCreate()
             }
         }
+        networkStateMonitor = NetworkStateMonitor(applicationContext)
+        networkStateMonitor.startMonitoring()
+    }
+
+    override fun onTerminate() {
+        super.onTerminate()
+        if (::networkStateMonitor.isInitialized) {
+            networkStateMonitor.stopMonitoring()
+        }
     }
 
     fun runOnWorkerThread(task: Runnable) {
diff --git a/app/src/main/java/jp/atled/agileworks/widget/NetworkStateMonitor.kt b/app/src/main/java/jp/atled/agileworks/widget/NetworkStateMonitor.kt
new file mode 100644
index 0000000000000000000000000000000000000000..8ffc799a68bec5fc3d59cc22f0edbfcf5cafbcc5
--- /dev/null
+++ b/app/src/main/java/jp/atled/agileworks/widget/NetworkStateMonitor.kt
@@ -0,0 +1,109 @@
+package jp.atled.agileworks.widget
+
+import android.content.Context
+import android.net.ConnectivityManager
+import android.net.Network
+import android.net.NetworkCapabilities
+import android.net.NetworkRequest
+import android.os.Handler
+import android.os.Looper
+import android.util.Log
+
+class NetworkStateMonitor(private val context: Context) {
+    private val TAG = "LoginFragment"
+    private val connectivityManager =
+        context.getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
+
+    private var isNetworkAvailable = false
+
+    private val debounceHandler = Handler(Looper.getMainLooper())
+    private var widgetUpdateRunnable: Runnable? = null
+    private val DEBOUNCE_DELAY_MS = 2000L
+
+    private val networkCallback = object : ConnectivityManager.NetworkCallback() {
+        override fun onAvailable(network: Network) {
+            super.onAvailable(network)
+            if (!isNetworkAvailable) {
+                isNetworkAvailable = true
+                scheduleWidgetUpdate()
+            }
+        }
+
+        override fun onLost(network: Network) {
+            super.onLost(network)
+            isNetworkAvailable = false
+            // ネットワークが失われたら、スケジュールされている更新はキャンセルする
+            cancelScheduledWidgetUpdate()
+        }
+
+        override fun onCapabilitiesChanged(
+            network: Network,
+            networkCapabilities: NetworkCapabilities
+        ) {
+            super.onCapabilitiesChanged(network, networkCapabilities)
+            val currentlyAvailable = networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) &&
+                    networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED)
+            if (currentlyAvailable) {
+                if (!isNetworkAvailable) {
+                    isNetworkAvailable = true
+                    scheduleWidgetUpdate() // WidgetUpdate.update() を直接呼ばず、スケジュールする
+                }
+            } else {
+                isNetworkAvailable = false
+                // ネットワークが利用不可になったら、スケジュールされている更新はキャンセルする
+                cancelScheduledWidgetUpdate()
+            }
+        }
+    }
+
+    private fun scheduleWidgetUpdate() {
+        // 既存のスケジュールがあればキャンセル
+        cancelScheduledWidgetUpdate()
+
+        // 新しいスケジュールを設定
+        widgetUpdateRunnable = Runnable {
+            WidgetUpdate.update()
+        }
+        debounceHandler.postDelayed(widgetUpdateRunnable!!, DEBOUNCE_DELAY_MS)
+        Log.d("TAG", "Widget update scheduled in ${DEBOUNCE_DELAY_MS}ms.")
+    }
+
+    private fun cancelScheduledWidgetUpdate() {
+        widgetUpdateRunnable?.let {
+            debounceHandler.removeCallbacks(it)
+        }
+        widgetUpdateRunnable = null
+    }
+
+    fun startMonitoring() {
+        val activeNetwork = connectivityManager.activeNetwork
+        if (activeNetwork != null) {
+            val networkCapabilities = connectivityManager.getNetworkCapabilities(activeNetwork)
+            isNetworkAvailable = networkCapabilities?.hasCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET) == true &&
+                    networkCapabilities.hasCapability(NetworkCapabilities.NET_CAPABILITY_VALIDATED) == true
+        } else {
+            isNetworkAvailable = false
+        }
+
+        val networkRequest = NetworkRequest.Builder()
+            .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
+            .build()
+        try {
+            connectivityManager.registerNetworkCallback(networkRequest, networkCallback)
+            Log.d(TAG, "Network monitoring started.")
+        } catch (e: SecurityException) {
+            Log.e(TAG, "Failed to register network callback. Check ACCESS_NETWORK_STATE permission.", e)
+        }
+    }
+
+    fun stopMonitoring() {
+        // 監視停止時にスケジュールされている更新もキャンセル
+        cancelScheduledWidgetUpdate()
+        try {
+            connectivityManager.unregisterNetworkCallback(networkCallback)
+            Log.d(TAG, "Network monitoring stopped.")
+        } catch (e: IllegalArgumentException) {
+            Log.w(TAG, "Failed to unregister network callback.", e)
+        }
+    }
+}
\ No newline at end of file