diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 827b9d4..0e9dd2e 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -12,13 +12,15 @@
         <activity android:name=".MainActivity" />
         <activity android:name=".Lesson1Activity" />
         <activity android:name=".Lesson2Activity" />
-        <activity android:name=".Lesson3Activity">
+        <activity android:name=".Lesson3Activity" />
+        <activity android:name=".Lesson4Activity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
 
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity android:name=".Lesson4SubActivity" />
     </application>
 
 </manifest>
\ No newline at end of file
diff --git a/app/src/main/java/com/example/Lesson4Activity.java b/app/src/main/java/com/example/Lesson4Activity.java
new file mode 100644
index 0000000..ab22a31
--- /dev/null
+++ b/app/src/main/java/com/example/Lesson4Activity.java
@@ -0,0 +1,66 @@
+package com.example;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.content.Intent;
+import android.os.Bundle;
+import android.util.Log;
+import android.view.View;
+import android.widget.Button;
+
+public class Lesson4Activity extends AppCompatActivity {
+    private final String TAG = "DEBUG_" + Lesson4Activity.class.getSimpleName();
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        Log.d(TAG, "onCreate");
+        setContentView(R.layout.activity_lesson4);
+
+        // Viewを取得
+        Button button = findViewById(R.id.lesson4_button);
+        button.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                Intent intent = new Intent(getApplicationContext(), Lesson4SubActivity.class);
+                startActivity(intent);
+            }
+        });
+    }
+
+    @Override
+    protected void onStart() {
+        super.onStart();
+        Log.d(TAG, "onStart");
+    }
+
+    @Override
+    protected void onRestart() {
+        super.onRestart();
+        Log.d(TAG, "onRestart");
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        Log.d(TAG, "onResume");
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+        Log.d(TAG, "onPause");
+    }
+
+    @Override
+    protected void onStop() {
+        super.onStop();
+        Log.d(TAG, "onStop");
+    }
+
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        Log.d(TAG, "onDestroy");
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/example/Lesson4SubActivity.java b/app/src/main/java/com/example/Lesson4SubActivity.java
new file mode 100644
index 0000000..1f4d5a2
--- /dev/null
+++ b/app/src/main/java/com/example/Lesson4SubActivity.java
@@ -0,0 +1,64 @@
+package com.example;
+
+import androidx.appcompat.app.AppCompatActivity;
+
+import android.os.Bundle;
+import android.util.Log;
+import android.view.View;
+import android.widget.Button;
+
+public class Lesson4SubActivity extends AppCompatActivity {
+    private final String TAG = "DEBUG_" + Lesson4SubActivity.class.getSimpleName();
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        Log.d(TAG, "onCreate");
+        setContentView(R.layout.activity_lesson4_sub);
+
+        // Viewを取得
+        Button button = findViewById(R.id.lesson4_sub_button);
+        button.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                finish();
+            }
+        });
+    }
+
+    @Override
+    protected void onStart() {
+        super.onStart();
+        Log.d(TAG, "onStart");
+    }
+
+    @Override
+    protected void onRestart() {
+        super.onRestart();
+        Log.d(TAG, "onRestart");
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+        Log.d(TAG, "onResume");
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+        Log.d(TAG, "onPause");
+    }
+
+    @Override
+    protected void onStop() {
+        super.onStop();
+        Log.d(TAG, "onStop");
+    }
+
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        Log.d(TAG, "onDestroy");
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_lesson4.xml b/app/src/main/res/layout/activity_lesson4.xml
new file mode 100644
index 0000000..22ea468
--- /dev/null
+++ b/app/src/main/res/layout/activity_lesson4.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".Lesson4Activity">
+
+    <TextView
+        android:id="@+id/lesson4_text_view"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/lesson4_text"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <Button
+        android:id="@+id/lesson4_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Button"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/lesson4_text_view" />
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_lesson4_sub.xml b/app/src/main/res/layout/activity_lesson4_sub.xml
new file mode 100644
index 0000000..71fc638
--- /dev/null
+++ b/app/src/main/res/layout/activity_lesson4_sub.xml
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".Lesson4SubActivity">
+
+    <TextView
+        android:id="@+id/lesson4_sub_text_view"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/lesson4_sub_text"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <Button
+        android:id="@+id/lesson4_sub_button"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Button"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@+id/lesson4_sub_text_view" />
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 188e2e1..5fc0f3f 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -16,4 +16,7 @@
         <item>土曜日</item>
         <item>日曜日</item>
     </string-array>
+    <!-- Lesson4 -->
+    <string name="lesson4_text">メイン画面です</string>
+    <string name="lesson4_sub_text">サブ画面です</string>
 </resources>
\ No newline at end of file