diff --git a/src/amountToHangul.spec.ts b/src/amountToHangul.spec.ts
index 7be66a5e..0ba591a6 100644
--- a/src/amountToHangul.spec.ts
+++ b/src/amountToHangul.spec.ts
@@ -7,6 +7,11 @@ describe('amountToHangul', () => {
     expect(amountToHangul('100000100')).toEqual('일억백');
   });
 
+  it('숫자로 된 금액이 80글자를 넘을 시 에러 발생', () => {
+    const longNumberString = '1'.repeat(81);    
+    expect(() => amountToHangul(longNumberString)).toThrowError(`convert range exceeded : ${longNumberString}`);
+  })
+  
   it('숫자 외 문자를 무시하여 반환', () => {
     expect(amountToHangul('120,030원')).toEqual('일십이만삼십');
   });