diff --git a/benchmark/range_bsearch.yml b/benchmark/range_bsearch.yml
new file mode 100644
index 0000000000..9a7388ab04
--- /dev/null
+++ b/benchmark/range_bsearch.yml
@@ -0,0 +1,9 @@
+prelude: |
+  r = (1..)
+
+benchmark:
+  '10**1': r.bsearch { |x| x >= 10 }
+  '10**2': r.bsearch { |x| x >= 100 }
+  '10**3': r.bsearch { |x| x >= 1000 }
+  '10**4': r.bsearch { |x| x >= 10000 }
+  '10**5': r.bsearch { |x| x >= 100000 }
diff --git a/range.c b/range.c
index 62e957e622..b18a25ea35 100644
--- a/range.c
+++ b/range.c
@@ -758,6 +758,7 @@ range_bsearch(VALUE range)
                 return bsearch_integer_range(beg, mid, 0);
             }
             diff = rb_funcall(diff, '*', 1, LONG2FIX(2));
+            beg = mid;
         }
     }
     else if (NIL_P(beg) && is_integer_p(end)) {
@@ -770,6 +771,7 @@ range_bsearch(VALUE range)
                 return bsearch_integer_range(mid, end, 0);
             }
             diff = rb_funcall(diff, '*', 1, LONG2FIX(2));
+            end = mid;
         }
     }
     else {