diff --git a/share/timedef/ja_JP.SJIS.src b/share/timedef/ja_JP.SJIS.src
index 57fd95ca32ee..ca6702dc588c 100644
--- a/share/timedef/ja_JP.SJIS.src
+++ b/share/timedef/ja_JP.SJIS.src
@@ -65,7 +65,7 @@
 #
 # just following tradition...
 # %a %b %e %H:%M:%S %Y
-%a %b/%e %T %Y
+%a %_m/%e %T %Y
 #
 # am
 #
diff --git a/share/timedef/ja_JP.UTF-8.src b/share/timedef/ja_JP.UTF-8.src
index 1ee99ca8af58..21d0eb50d199 100644
--- a/share/timedef/ja_JP.UTF-8.src
+++ b/share/timedef/ja_JP.UTF-8.src
@@ -64,7 +64,7 @@
 #
 # just following tradition...
 # %a %b %e %H:%M:%S %Y
-%a %b/%e %T %Y
+%a %_m/%e %T %Y
 #
 # am
 #
diff --git a/share/timedef/ja_JP.eucJP.src b/share/timedef/ja_JP.eucJP.src
index 218b2e90e4b8..155d227c4c58 100644
--- a/share/timedef/ja_JP.eucJP.src
+++ b/share/timedef/ja_JP.eucJP.src
@@ -64,7 +64,7 @@
 #
 # just following tradition...
 # %a %b %e %H:%M:%S %Y
-%a %b/%e %T %Y
+%a %_m/%e %T %Y
 #
 # am
 #