diff --git a/ChangeLog b/ChangeLog
index 6813769938..56615e4817 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Apr 12 13:52:18 2015  SHIBATA Hiroshi  <shibata.hiroshi@gmail.com>
+
+	* ext/coverage/coverage.c: Remove extension from require argument.
+	  [ci skip][fix GH-870] Patch by @yui-knk
+
 Sun Apr 12 10:29:14 2015  Eric Wong  <e@80x24.org>
 
 	* ext/openssl/ossl_ssl.c (ossl_ssl_connect_nonblock):
diff --git a/ext/coverage/coverage.c b/ext/coverage/coverage.c
index ed4a69d3db..0c7755bc6d 100644
--- a/ext/coverage/coverage.c
+++ b/ext/coverage/coverage.c
@@ -93,7 +93,7 @@ rb_coverage_result(VALUE klass)
  *
  * = Usage
  *
- * 1. require "coverage.so"
+ * 1. require "coverage"
  * 2. do Coverage.start
  * 3. require or load Ruby source file
  * 4. Coverage.result will return a hash that contains filename as key and
@@ -116,7 +116,7 @@ rb_coverage_result(VALUE klass)
  *   end
  *   [EOF]
  *
- *   require "coverage.so"
+ *   require "coverage"
  *   Coverage.start
  *   require "foo.rb"
  *   p Coverage.result  #=> {"foo.rb"=>[1, 1, 10, nil, nil, 1, 1, nil, 0, nil]}