diff --git a/tool/downloader.rb b/tool/downloader.rb
index fcf456bd53..1bad317ae5 100644
--- a/tool/downloader.rb
+++ b/tool/downloader.rb
@@ -91,7 +91,7 @@ class Downloader
         options['If-Modified-Since'] = since
       end
     end
-    options['Accept-Encoding'] = '*' # to deisable Net::HTTP::GenericRequest#decode_content
+    options['Accept-Encoding'] = '*' # to disable Net::HTTP::GenericRequest#decode_content
     options
   end