diff --git a/ext/objspace/objspace.c b/ext/objspace/objspace.c
index ba138e6244..ee76367b44 100644
--- a/ext/objspace/objspace.c
+++ b/ext/objspace/objspace.c
@@ -203,7 +203,7 @@ type2sym(enum ruby_value_type i)
  *
  *  Note that this information is incomplete.  You need to deal with
  *  this information as only a *HINT*.  Especially, total size of
- *  T_DATA may not right size.
+ *  T_DATA may be wrong.
  *
  *  It returns a hash as:
  *    {:TOTAL=>1461154, :T_CLASS=>158280, :T_MODULE=>20672, :T_STRING=>527249, ...}
@@ -232,13 +232,6 @@ count_objects_size(int argc, VALUE *argv, VALUE os)
 
     rb_objspace_each_objects(cos_i, &counts[0]);
 
-    if (hash == Qnil) {
-        hash = rb_hash_new();
-    }
-    else if (!RHASH_EMPTY_P(hash)) {
-        st_foreach(RHASH_TBL(hash), set_zero_i, hash);
-    }
-
     for (i = 0; i <= T_MASK; i++) {
 	if (counts[i]) {
 	    VALUE type = type2sym(i);
@@ -313,13 +306,6 @@ count_symbols(int argc, VALUE *argv, VALUE os)
     size_t immortal_symbols = rb_sym_immortal_count();
     rb_objspace_each_objects(cs_i, &dynamic_counts);
 
-    if (hash == Qnil) {
-        hash = rb_hash_new();
-    }
-    else if (!RHASH_EMPTY_P(hash)) {
-        st_foreach(RHASH_TBL(hash), set_zero_i, hash);
-    }
-
     rb_hash_aset(hash, ID2SYM(rb_intern("mortal_dynamic_symbol")),   SIZET2NUM(dynamic_counts.mortal));
     rb_hash_aset(hash, ID2SYM(rb_intern("immortal_dynamic_symbol")), SIZET2NUM(dynamic_counts.immortal));
     rb_hash_aset(hash, ID2SYM(rb_intern("immortal_static_symbol")),  SIZET2NUM(immortal_symbols - dynamic_counts.immortal));
@@ -380,13 +366,6 @@ count_nodes(int argc, VALUE *argv, VALUE os)
 
     rb_objspace_each_objects(cn_i, &nodes[0]);
 
-    if (hash == Qnil) {
-        hash = rb_hash_new();
-    }
-    else if (!RHASH_EMPTY_P(hash)) {
-        st_foreach(RHASH_TBL(hash), set_zero_i, hash);
-    }
-
     for (i=0; i<NODE_LAST; i++) {
 	if (nodes[i] != 0) {
 	    VALUE node;
diff --git a/test/objspace/test_objspace.rb b/test/objspace/test_objspace.rb
index c5c8147f5f..9c706f2736 100644
--- a/test/objspace/test_objspace.rb
+++ b/test/objspace/test_objspace.rb
@@ -61,9 +61,19 @@ class TestObjSpace < Test::Unit::TestCase
     res = ObjectSpace.count_objects_size
     assert_not_empty(res)
     assert_operator(res[:TOTAL], :>, 0)
+  end
+
+  def test_count_objects_size_with_hash
     arg = {}
     ObjectSpace.count_objects_size(arg)
     assert_not_empty(arg)
+    arg = {:TOTAL => 1 }
+    ObjectSpace.count_objects_size(arg)
+    assert_not_empty(arg)
+  end
+
+  def test_count_objects_size_with_wrong_type
+    assert_raise(TypeError) { ObjectSpace.count_objects_size(0) }
   end
 
   def test_count_nodes