diff --git a/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java
new file mode 100644
index 0000000..3f0ca2c
--- /dev/null
+++ b/app/src/main/java/com/example/tampopo_client/viewmodels/ChatViewModel.java
@@ -0,0 +1,33 @@
+package com.example.tampopo_client.viewmodels;
+
+import android.util.Log;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class ChatViewModel extends RealTimeViewModel {
+    private final List<NotificationListener> notificationListeners = new ArrayList<>();
+
+    private static final double NOTIFICATION_RECEIVE_PROBABILITY = 0.01;
+
+    @Override
+    public Runnable onUpdate() {
+        return () -> {
+            // 1% の確率で onNotificationReceived() が呼び出される
+            double borderValue = Math.floor(Math.random() * 100);
+            double currentValue = NOTIFICATION_RECEIVE_PROBABILITY * 100;
+            if (currentValue >= borderValue) {
+                Log.d("ChatViewModel", "Received test notification.");
+                notificationListeners.forEach(listener -> listener.onNotificationReceived());
+            }
+        };
+    }
+
+    public void addNotificationListener(NotificationListener listener) {
+        notificationListeners.add(listener);
+    }
+
+    public void clearNotificationListener() {
+        notificationListeners.clear();
+    }
+}
diff --git a/app/src/main/java/com/example/tampopo_client/viewmodels/NotificationListener.java b/app/src/main/java/com/example/tampopo_client/viewmodels/NotificationListener.java
new file mode 100644
index 0000000..772483c
--- /dev/null
+++ b/app/src/main/java/com/example/tampopo_client/viewmodels/NotificationListener.java
@@ -0,0 +1,5 @@
+package com.example.tampopo_client.viewmodels;
+
+public interface NotificationListener {
+    void onNotificationReceived();
+}
diff --git a/app/src/main/java/com/example/tampopo_client/views/MainActivity.java b/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
index 40c8179..984f8b7 100644
--- a/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
+++ b/app/src/main/java/com/example/tampopo_client/views/MainActivity.java
@@ -27,10 +27,12 @@
 import com.example.tampopo_client.models.Activity;
 import com.example.tampopo_client.viewmodels.ActivityViewModel;
 import com.example.tampopo_client.viewmodels.ActivityViewModelFactory;
+import com.example.tampopo_client.viewmodels.ChatViewModel;
+import com.example.tampopo_client.viewmodels.NotificationListener;
 
 import java.util.Map;
 
-public class MainActivity extends AppCompatActivity {
+public class MainActivity extends AppCompatActivity implements NotificationListener {
 
     private EditText editMessage;
     private ImageButton sendButton;
@@ -44,6 +46,7 @@
     ActivityViewModel activityViewModel;
     Tampopo tampopo;
 
+    private ChatViewModel chatViewModel;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -72,6 +75,9 @@
         ActivityViewModelFactory factory = new ActivityViewModelFactory(tampopo.getUserId(), tampopo.getToken()); // Factoryを使って、引数をコンストラクタにわたしつつViewModelを作成
         activityViewModel = new ViewModelProvider(this, factory).get(ActivityViewModel.class);
 
+        // ChatViewModelを初期化する
+        chatViewModel = new ViewModelProvider(this).get(ChatViewModel.class);
+
 
 //        MutableLiveData<List<String>>friendUserIdsLiveDate = activityViewModel.getFriendUserIdsLiveData();
 //        friendUserIdsLiveDate.observe(this, new Observer<List<String>>() {
@@ -124,6 +130,9 @@
         if (activityViewModel != null) {
             activityViewModel.startUpdating(1L);
         }
+        if (chatViewModel != null) {
+            chatViewModel.startUpdating(1L);
+        }
     }
 
     @Override
@@ -133,6 +142,9 @@
         if (activityViewModel != null) {
             activityViewModel.stopUpdating();
         }
+        if (chatViewModel != null) {
+            chatViewModel.stopUpdating();
+        }
     }
 
     @Override
@@ -142,6 +154,9 @@
         if (activityViewModel != null) {
             activityViewModel.stopUpdating();
         }
+        if (chatViewModel != null) {
+            chatViewModel.stopUpdating();
+        }
     }
 
     private void showInputDialog() {
@@ -222,4 +237,8 @@
 //        }
     }
 
+    @Override
+    public void onNotificationReceived() {
+        // TODO: 通知を受信したときの処理を実装する
+    }
 }
\ No newline at end of file