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();
+    }
+}