diff --git a/src/amountToHangul.spec.ts b/src/amountToHangul.spec.ts
index 3d2de30b..71fd12e5 100644
--- a/src/amountToHangul.spec.ts
+++ b/src/amountToHangul.spec.ts
@@ -8,4 +8,9 @@ describe('amountToHangul', () => {
     expect(amountToHangul('100000000')).toEqual('일억');
     expect(amountToHangul('100000100')).toEqual('일억백');
   });
+
+  it('숫자로 된 금액이 80글자를 넘을 시 에러 발생', () => {
+    const longNumberString = '123456789012345678901234567890123456789012345678901234567890123456789012345678901';
+    expect(() => amountToHangul(longNumberString)).toThrowError(`convert range exceeded : ${longNumberString}`);
+  });
 });