diff --git a/ChangeLog b/ChangeLog
index 592606c93a..1bae89f159 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sat Nov 21 13:59:09 2015  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* ext/digest/sha1/extconf.rb: OpenSSL's struct name for SHA1 is
+	  SHA_CTX. http://openssl.org/docs/man0.9.8/crypto/SHA1.html
+
 Sat Nov 21 13:31:52 2015  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* ext/digest/*/*.[ch]: include ruby.h before digest.h to avoid
diff --git a/ext/digest/sha1/extconf.rb b/ext/digest/sha1/extconf.rb
index 84690e8ea5..b5c111f36e 100644
--- a/ext/digest/sha1/extconf.rb
+++ b/ext/digest/sha1/extconf.rb
@@ -9,7 +9,7 @@ $defs << "-DHAVE_CONFIG_H"
 
 $objs = [ "sha1init.#{$OBJEXT}" ]
 
-digest_conf("sha1", "sha")
+digest_conf("sha1", "sha", "SHA")
 
 have_header("sys/cdefs.h")