diff --git a/ChangeLog b/ChangeLog
index 9740541e62..e6f0bc0f6b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Thu Feb 27 12:10:09 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* numeric.c (ruby_num_interval_step_size): check signs and get rid
+	  of implementation dependent behavior of negative division.
+	  [ruby-core:61106] [Bug #9570]
+
 Thu Feb 27 03:55:45 2014  Zachary Scott  <e@zzak.io>
 
 	* thread.c: [DOC] Typo in comment for _FORTIFY_SOURCE [Fixes GH-548]
diff --git a/numeric.c b/numeric.c
index 838ec43c29..99a1c7d60e 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1808,10 +1808,21 @@ ruby_num_interval_step_size(VALUE from, VALUE to, VALUE step, int excl)
 	long delta, diff, result;
 
 	diff = FIX2LONG(step);
+	if (!diff) rb_num_zerodiv();
 	delta = FIX2LONG(to) - FIX2LONG(from);
 	if (excl) {
 	    delta += (diff > 0 ? -1 : +1);
 	}
+	if (delta) {
+	    if (diff < 0) {
+		if (delta > 0) return INT2FIX(0);
+		diff = -diff;
+		delta = -delta;
+	    }
+	    else {
+		if (delta < 0) return INT2FIX(0);
+	    }
+	}
 	result = delta / diff;
 	return LONG2FIX(result >= 0 ? result + 1 : 0);
     }
diff --git a/test/ruby/test_numeric.rb b/test/ruby/test_numeric.rb
index 44c12ede9c..25351163b7 100644
--- a/test/ruby/test_numeric.rb
+++ b/test/ruby/test_numeric.rb
@@ -279,6 +279,8 @@ class TestNumeric < Test::Unit::TestCase
     assert_step [1], [1, 10, 2**32]
     assert_step [1], [1, to: 10, by: 2**32]
 
+    assert_step [], [2, 1, 3]
+    assert_step [], [-2, -1, -3]
     assert_step [3, 3, 3, 3], [3, by: 0], inf: true
     assert_step [10], [10, 1, -(2**32)]