diff --git a/README.ja.md b/README.ja.md
index bd6b7e0..8657633 100644
--- a/README.ja.md
+++ b/README.ja.md
@@ -15,7 +15,8 @@
 
 <!-- START doctoc generated TOC please keep comment here to allow auto update -->
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
-**Table of Contents**
+<details>
+<summary>Details</summary>
 
 - [スクリーンショット](#%E3%82%B9%E3%82%AF%E3%83%AA%E3%83%BC%E3%83%B3%E3%82%B7%E3%83%A7%E3%83%83%E3%83%88)
   - [動作](#%E5%8B%95%E4%BD%9C)
@@ -36,6 +37,7 @@
   - [例1: 色の変更](#%E4%BE%8B1-%E8%89%B2%E3%81%AE%E5%A4%89%E6%9B%B4)
   - [例2: 複数設定](#%E4%BE%8B2-%E8%A4%87%E6%95%B0%E8%A8%AD%E5%AE%9A)
 
+</details>
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
 ## スクリーンショット
diff --git a/README.md b/README.md
index 2d0411d..8d4049b 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,8 @@ jQuery plugin to add under line animation like highlighter.
 
 <!-- START doctoc generated TOC please keep comment here to allow auto update -->
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
-**Table of Contents**
+<details>
+<summary>Details</summary>
 
 - [Screenshot](#screenshot)
   - [Behavior](#behavior)
@@ -36,6 +37,7 @@ jQuery plugin to add under line animation like highlighter.
   - [e.g. Change color](#eg-change-color)
   - [e.g Multiple options](#eg-multiple-options)
 
+</details>
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
 ## Screenshot