diff --git a/ChangeLog b/ChangeLog
index 571bb7cfd0..bb29100a4b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Jul  4 04:42:05 2014  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* lib/net/htp/response.rb (Net::Inflater#inflate_adapter):
+	  prevent automatic encoding conversion.
+
 Fri Jul  4 04:39:52 2014  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/net/http/response.rb (Net::HTTPResponse.each_response_header):
diff --git a/lib/net/http/response.rb b/lib/net/http/response.rb
index 33a7804cdc..45115295d9 100644
--- a/lib/net/http/response.rb
+++ b/lib/net/http/response.rb
@@ -369,6 +369,11 @@ class Net::HTTPResponse
     # entire body in memory.
 
     def inflate_adapter(dest)
+      if dest.respond_to?(:set_encoding)
+        dest.set_encoding(Encoding::ASCII_8BIT)
+      elsif dest.respond_to?(:force_encoding)
+        dest.force_encoding(Encoding::ASCII_8BIT)
+      end
       block = proc do |compressed_chunk|
         @inflate.inflate(compressed_chunk) do |chunk|
           dest << chunk