diff --git a/.gitignore b/.gitignore
new file mode 100644
index 00000000..c2658d7d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules/
diff --git a/gulpfile.js b/gulpfile.js
new file mode 100644
index 00000000..a902bfd1
--- /dev/null
+++ b/gulpfile.js
@@ -0,0 +1,23 @@
+'use strict';
+
+var gulp = require('gulp');
+var prettify = require('gulp-jsbeautifier');
+
+var sources = ['**/*.js', '**/*.css', '**/*.html', '!node_modules/**'];
+
+gulp.task('prettify', function() {
+  gulp.src(sources)
+    .pipe(prettify({
+      html: {
+        indentSize: 2
+      },
+      css: {
+        indentSize: 2
+      },
+      js: {
+        indentSize: 2,
+        braceStyle: "end-expand"
+      }
+    }))
+    .pipe(gulp.dest('.'));
+});
diff --git a/package.json b/package.json
index d7879911..8a9c594b 100644
--- a/package.json
+++ b/package.json
@@ -4,5 +4,9 @@
   "description": "",
   "main": "main.js",
   "author": "Yuya Ochiai",
-  "license": "MIT"
+  "license": "MIT",
+  "devDependencies": {
+    "gulp": "^3.9.0",
+    "gulp-jsbeautifier": "^1.0.1"
+  }
 }