diff --git a/src/main/java/video/domain/Customer.java b/src/main/java/video/domain/Customer.java
index fd4af2f..ee09a48 100644
--- a/src/main/java/video/domain/Customer.java
+++ b/src/main/java/video/domain/Customer.java
@@ -27,7 +27,7 @@ public RentalResult rentalMovies() {
         int totalAmount = 0;
         int frequentRenterPoints = 0;
         for (Rental each : rentals) {
-            int thisAmount = amount(each);
+            int thisAmount = each.amount();
             // レンタルポイントを加算
             frequentRenterPoints++;
             // 新作を二日以上借りた場合はボーナスポイント
@@ -39,24 +39,4 @@ public RentalResult rentalMovies() {
         return new RentalResult(totalAmount, frequentRenterPoints);
     }
 
-    private int amount(Rental each) {
-        int thisAmount = 0;
-        // 金額を計算
-        switch (each.getMovie().getPriceType()) {
-            case REGULAR:
-                thisAmount += 200;
-                if (each.getDaysRented() > 2)
-                    thisAmount += (each.getDaysRented() - 2) * 150;
-                break;
-            case NEW_RELEASE:
-                thisAmount += each.getDaysRented() * 300;
-                break;
-            case CHILDREN:
-                thisAmount += 150;
-                if (each.getDaysRented() > 3)
-                    thisAmount += (each.getDaysRented() - 3) * 150;
-                break;
-        }
-        return thisAmount;
-    }
 }
\ No newline at end of file
diff --git a/src/main/java/video/domain/Rental.java b/src/main/java/video/domain/Rental.java
index 7e33b3f..796858a 100644
--- a/src/main/java/video/domain/Rental.java
+++ b/src/main/java/video/domain/Rental.java
@@ -16,4 +16,25 @@ public int getDaysRented() {
     public Movie getMovie() {
         return movie;
     }
+
+    int amount() {
+        int thisAmount = 0;
+        // 金額を計算
+        switch (getMovie().getPriceType()) {
+            case REGULAR:
+                thisAmount += 200;
+                if (getDaysRented() > 2)
+                    thisAmount += (getDaysRented() - 2) * 150;
+                break;
+            case NEW_RELEASE:
+                thisAmount += getDaysRented() * 300;
+                break;
+            case CHILDREN:
+                thisAmount += 150;
+                if (getDaysRented() > 3)
+                    thisAmount += (getDaysRented() - 3) * 150;
+                break;
+        }
+        return thisAmount;
+    }
 }
\ No newline at end of file
diff --git a/src/test/java/video/domain/RentalTest.java b/src/test/java/video/domain/RentalTest.java
new file mode 100644
index 0000000..bf868bc
--- /dev/null
+++ b/src/test/java/video/domain/RentalTest.java
@@ -0,0 +1,57 @@
+package video.domain;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class RentalTest {
+
+    Movie 子供用作品_となりのトトロ = new Movie("となりのトトロ", PriceType.CHILDREN);
+    Movie 旧作_トップガン = new Movie("トップガン", PriceType.REGULAR);
+    Movie 新作_君たちはどう生きるか = new Movie("君たちはどう生きるか", PriceType.NEW_RELEASE);
+    @Test
+    void 新作を4日のレンタル料金() {
+        Rental sut = new Rental(新作_君たちはどう生きるか, 4);
+
+        double result = sut.amount();
+
+        assertEquals(1200, result);
+    }
+
+
+    @Test
+    void 旧作を2日のレンタル料金() {
+        Rental sut = new Rental(旧作_トップガン, 2);
+
+        double result = sut.amount();
+
+        assertEquals(200, result);
+    }
+
+    @Test
+    void 旧作を3日のレンタル料金() {
+        Rental sut = new Rental(旧作_トップガン, 3);
+
+        double result = sut.amount();
+
+        assertEquals(350, result);
+    }
+
+    @Test
+    void 子供用作品を4日のレンタル料金() {
+        Rental sut = new Rental(子供用作品_となりのトトロ, 4);
+
+        double result = sut.amount();
+
+        assertEquals(300, result);
+    }
+
+    @Test
+    void 子供用作品を3日のレンタル料金() {
+        Rental sut = new Rental(子供用作品_となりのトトロ, 3);
+
+        double result = sut.amount();
+
+        assertEquals(150, result);
+    }
+}
\ No newline at end of file