diff --git a/tool/make-snapshot b/tool/make-snapshot
index 0b3d284a90..cac32d359d 100755
--- a/tool/make-snapshot
+++ b/tool/make-snapshot
@@ -286,7 +286,7 @@ def package(vcs, rev, destdir, tmp = nil)
     v = v[0]
   end
 
-  open("#{v}/revision.h", "wb") {|f| f.puts "#define RUBY_REVISION #{revision}"}
+  open("#{v}/revision.h", "wb") {|f| f.puts "#define RUBY_REVISION #{revision.dump}"}
   version ||= (versionhdr = IO.read("#{v}/version.h"))[RUBY_VERSION_PATTERN, 1]
   version ||=
     begin