diff --git a/tool/redmine-backporter.rb b/tool/redmine-backporter.rb
index 475054641b..7f08eb8d1a 100755
--- a/tool/redmine-backporter.rb
+++ b/tool/redmine-backporter.rb
@@ -353,14 +353,14 @@ eom
 
     if rev && has_commit(rev, "ruby_#{TARGET_VERSION.tr('.','_')}")
       notes = "ruby_#{TARGET_VERSION.tr('.','_')} commit:#{rev}."
-    elsif rev.nil? && (log = find_git_log("##@issue]")) && /^commit (?<rev>\h{40})$/ =~ log
-      str = log[/merge revision\(s\) ([^:]+)(?=:)/]
-      if str
-        str.sub!(/\Amerge/, 'merged')
-        str.gsub!(/\h{8,40}/, 'commit:\0')
-        str = "ruby_#{TARGET_VERSION.tr('.','_')} commit:#{rev} #{str}."
+    elsif rev.nil? && (log = find_git_log("##@issue]")) && !(revs = log.scan(/^commit (\h{40})$/).flatten).empty?
+      commits = revs.map { |rev| "commit:#{rev}" }.join(", ")
+      if merged_revs = log[/merge revision\(s\) ([^:]+)(?=:)/]
+        merged_revs.sub!(/\Amerge/, 'merged')
+        merged_revs.gsub!(/\h{8,40}/, 'commit:\0')
+        str = "ruby_#{TARGET_VERSION.tr('.','_')} #{commits} #{merged_revs}."
       else
-        str = "ruby_#{TARGET_VERSION.tr('.','_')} commit:#{rev}."
+        str = "ruby_#{TARGET_VERSION.tr('.','_')} #{commits}."
       end
       if notes
         str << "\n"