diff --git a/mrbgems/mruby-string-ext/test/string.rb b/mrbgems/mruby-string-ext/test/string.rb
index 9de02c59f..0400a8da5 100644
--- a/mrbgems/mruby-string-ext/test/string.rb
+++ b/mrbgems/mruby-string-ext/test/string.rb
@@ -1,4 +1,3 @@
-# coding: utf-8
 ##
 # String(Ext) Test