diff --git a/README.md b/README.md
index 9cb13b3..a8f57ce 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,3 @@
 # Jest ハンズオン
 
-[![Edit in CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/kou029w/jest-hands-on)
+[![Edit in CodeSandbox](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/github/kou029w/jest-hands-on?file=/src/sum.test.js)