diff --git a/ext/oj/parse.c b/ext/oj/parse.c
index 7144b951..c2079eae 100644
--- a/ext/oj/parse.c
+++ b/ext/oj/parse.c
@@ -453,6 +453,7 @@ read_num(ParseInfo pi) {
 	    // except when mimicing the JSON gem or in strict mode.
 	    if (StrictMode == pi->options.mode || CompatMode == pi->options.mode) {
 		int	pos = (int)(pi->cur - ni.str);
+
 		if (1 == pos || (2 == pos && ni.neg)) {
 		    oj_set_error_at(pi, oj_parse_error_class, __FILE__, __LINE__, "not a number");
 		    return;
@@ -468,11 +469,19 @@ read_num(ParseInfo pi) {
 		if (0 < ni.num || 0 < ni.i) {
 		    dec_cnt++;
 		}
-		ni.num = ni.num * 10 + d;
-		ni.div *= 10;
-		ni.di++;
-		if (INT64_MAX <= ni.div || DEC_MAX < dec_cnt) {
-		    ni.big = 1;
+		if (INT64_MAX <= ni.div) {
+		    if (!ni.no_big) {
+			ni.big = true;
+		    }
+		} else {
+		    ni.num = ni.num * 10 + d;
+		    ni.div *= 10;
+		    ni.di++;
+		    if (INT64_MAX <= ni.div || DEC_MAX < dec_cnt) {
+			if (!ni.no_big) {
+			    ni.big = true;
+			}
+		    }
 		}
 	    }
 	}
@@ -490,7 +499,7 @@ read_num(ParseInfo pi) {
 	    for (; '0' <= *pi->cur && *pi->cur <= '9'; pi->cur++) {
 		ni.exp = ni.exp * 10 + (*pi->cur - '0');
 		if (EXP_MAX <= ni.exp) {
-		    ni.big = 1;
+		    ni.big = true;
 		}
 	    }
 	    if (eneg) {
diff --git a/test/test_custom.rb b/test/test_custom.rb
index 072c2070..9fac0c6d 100755
--- a/test/test_custom.rb
+++ b/test/test_custom.rb
@@ -118,6 +118,11 @@ def test_float
     dump_and_load(-2.48e100 * 1.0e10, false)
   end
 
+  def test_float_parse
+    f = Oj.load("12.123456789012345678", mode: :custom, bigdecimal_load: :float);
+    assert_equal(Float, f.class)
+  end
+
   def test_nan_dump
     assert_equal('null', Oj.dump(0/0.0, :nan => :null))
     assert_equal('3.3e14159265358979323846', Oj.dump(0/0.0, :nan => :huge))