diff --git a/ChangeLog b/ChangeLog
index c72c3186fd..bd7fa692a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun May  8 19:04:15 2011  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* lib/time.rb (xmlschema): avoid passing any negative numbers.
+
 Sun May  8 18:40:03 2011  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* ext/date/date_{parse,strptime}.c: introduced some macros.
diff --git a/lib/time.rb b/lib/time.rb
index 7186531387..ffccdeca5e 100644
--- a/lib/time.rb
+++ b/lib/time.rb
@@ -519,7 +519,7 @@ class Time
   def xmlschema(fraction_digits=0)
     sprintf('%0*d-%02d-%02dT%02d:%02d:%02d',
       year < 0 ? 5 : 4, year, mon, day, hour, min, sec) +
-    if fraction_digits == 0
+    if fraction_digits <= 0
       ''
     else
       '.' + sprintf('%0*d', fraction_digits, (subsec * 10**fraction_digits).floor)