diff --git a/ChangeLog b/ChangeLog
index 46e898addc..40245a58ac 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Mar 21 17:14:49 2010  Tanaka Akira  <akr@fsij.org>
+
+	* tool/transcode-tblgen.rb: reuse hash object.
+
 Sun Mar 21 12:32:39 2010  Tanaka Akira  <akr@fsij.org>
 
 	* tool/transcode-tblgen.rb (transcode_compile_tree): make
diff --git a/tool/transcode-tblgen.rb b/tool/transcode-tblgen.rb
index ba7855b71a..edc8db72a9 100755
--- a/tool/transcode-tblgen.rb
+++ b/tool/transcode-tblgen.rb
@@ -285,10 +285,11 @@ class ActionMap
     ret
   end
 
+  TMPHASH = {}
   def self.expand_rec(prefix, region_rects, &block)
     return region_rects if region_rects.empty? && !((s_rect = @singleton_rects.last) && s_rect[0].start_with?(prefix))
     if region_rects.empty? ? s_rect[0].length == prefix.length : region_rects[0][0].empty?
-      h = {}
+      h = TMPHASH
       while (s_rect = @singleton_rects.last) && s_rect[0].start_with?(prefix)
         min, max, action = @singleton_rects.pop
         raise ArgumentError, "ambiguous pattern: #{prefix}" if min.length != prefix.length
@@ -316,7 +317,7 @@ class ActionMap
   end
 
   def self.each_firstbyte_range(prefix, region_rects)
-    index_from = {}
+    index_from = TMPHASH
 
     region_ary = []
     region_rects.each {|min, max, action|