diff --git a/ChangeLog b/ChangeLog
index 52d38dbd15..1bcfad895e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Aug 13 08:47:20 2011  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* ext/date/date_core.c: [ruby-core:38855].
+
 Sat Aug 13 03:41:37 2011  Eric Hodel  <drbrain@segment7.net>
 
 	* lib/uri/common.rb:  Fix documentation of URI::Parser.new.  Patch by
diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 08328b9e8f..6474074028 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -4089,6 +4089,9 @@ d_new_by_frags(VALUE klass, VALUE hash, VALUE sg)
 	rb_warning("invalid start is ignored");
     }
 
+    if (NIL_P(hash))
+	rb_raise(rb_eArgError, "invalid date");
+
     if (NIL_P(ref_hash("jd")) &&
 	NIL_P(ref_hash("yday")) &&
 	!NIL_P(ref_hash("year")) &&
@@ -7853,6 +7856,9 @@ dt_new_by_frags(VALUE klass, VALUE hash, VALUE sg)
 	rb_warning("invalid start is ignored");
     }
 
+    if (NIL_P(hash))
+	rb_raise(rb_eArgError, "invalid date");
+
     if (NIL_P(ref_hash("jd")) &&
 	NIL_P(ref_hash("yday")) &&
 	!NIL_P(ref_hash("year")) &&