diff --git a/numeric.c b/numeric.c
index 5cb1aad8a1..697d692f0b 100644
--- a/numeric.c
+++ b/numeric.c
@@ -2514,9 +2514,10 @@ int
 ruby_float_step(VALUE from, VALUE to, VALUE step, int excl, int allow_endless)
 {
     if (RB_TYPE_P(from, T_FLOAT) || RB_TYPE_P(to, T_FLOAT) || RB_TYPE_P(step, T_FLOAT)) {
-	double beg = NUM2DBL(from);
-	double end = (allow_endless && NIL_P(to)) ? HUGE_VAL : NUM2DBL(to);
 	double unit = NUM2DBL(step);
+	double beg = NUM2DBL(from);
+	double end = (allow_endless && NIL_P(to)) ?
+	    (unit < 0 ? -HUGE_VAL : HUGE_VAL) : NUM2DBL(to);
 	double n = ruby_float_step_size(beg, end, unit, excl);
 	long i;
 
diff --git a/test/ruby/test_numeric.rb b/test/ruby/test_numeric.rb
index e48c3448e8..5947a33fd6 100644
--- a/test/ruby/test_numeric.rb
+++ b/test/ruby/test_numeric.rb
@@ -308,6 +308,11 @@ def test_step
     assert_step [10, 8, 6, 4, 2], [10, to: 1, by: -2]
     assert_step [1.0, 3.0, 5.0, 7.0, 9.0], [1.0, 10.0, 2.0]
     assert_step [1.0, 3.0, 5.0, 7.0, 9.0], [1.0, to: 10.0, by: 2.0]
+    assert_step [10.0, 8.0, 6.0, 4.0, 2.0], [10.0, 1, -2]
+    assert_step [10.0, 8.0, 6.0, 4.0, 2.0], [10.0, to: 1, by: -2]
+    assert_step [10.0, 8.0, 6.0, 4.0, 2.0], [10.0, 1, -2]
+    assert_step [10.0, 8.0, 6.0, 4.0, 2.0], [10, to: 1.0, by: -2]
+    assert_step [10.0, 8.0, 6.0, 4.0, 2.0], [10, 1.0, -2]
     assert_step [1], [1, 10, bignum]
     assert_step [1], [1, to: 10, by: bignum]
 
@@ -324,6 +329,11 @@ def test_step
     assert_step [10, 11, 12, 13], [10], inf: true
     assert_step [10, 9, 8, 7], [10, by: -1], inf: true
     assert_step [10, 9, 8, 7], [10, by: -1, to: nil], inf: true
+    assert_step [10.0, 9.0, 8.0, 7.0], [10, by: -1.0], inf: true
+    assert_step [10.0, 9.0, 8.0, 7.0], [10, by: -1.0, to: nil], inf: true
+    assert_step [10.0, 9.0, 8.0, 7.0], [10, nil, -1.0], inf: true
+    assert_step [10.0, 9.0, 8.0, 7.0], [10.0, by: -1], inf: true
+    assert_step [10.0, 9.0, 8.0, 7.0], [10.0, nil, -1], inf: true
 
     assert_step [42, 42, 42, 42], [42, by: 0, to: -Float::INFINITY], inf: true
     assert_step [42, 42, 42, 42], [42, by: 0, to: 42.5], inf: true