diff --git a/lib/rdoc/generator/json_index.rb b/lib/rdoc/generator/json_index.rb
index 9d6f0d4356..e5756c8996 100644
--- a/lib/rdoc/generator/json_index.rb
+++ b/lib/rdoc/generator/json_index.rb
@@ -170,7 +170,7 @@ def generate_gzipped
 
     Zlib::GzipWriter.open(outfile) do |gz|
       gz.mtime = File.mtime(search_index_file)
-      gz.orig_name = search_index_file.to_s
+      gz.orig_name = search_index_file.basename.to_s
       gz.write search_index
       gz.close
     end
@@ -188,7 +188,7 @@ def generate_gzipped
 
         Zlib::GzipWriter.open(outfile) do |gz|
           gz.mtime = File.mtime(dest)
-          gz.orig_name = dest.to_s
+          gz.orig_name = dest.basename.to_s
           gz.write data
           gz.close
         end