diff --git a/ext/oj/dump.c b/ext/oj/dump.c
index 07b4eec2..1d449388 100644
--- a/ext/oj/dump.c
+++ b/ext/oj/dump.c
@@ -708,10 +708,10 @@ void oj_write_obj_to_stream(VALUE obj, VALUE stream, Options copts) {
 }
 
 void oj_dump_str(VALUE obj, int depth, Out out, bool as_ok) {
-    rb_encoding *enc = rb_to_encoding(rb_obj_encoding(obj));
+    rb_encoding *enc = rb_enc_get(obj);
 
-    if (rb_utf8_encoding() != enc) {
-        obj = rb_str_conv_enc(obj, enc, rb_utf8_encoding());
+    if (oj_utf8_encoding != enc) {
+        obj = rb_str_conv_enc(obj, enc, oj_utf8_encoding);
     }
     oj_dump_cstr(RSTRING_PTR(obj), (int)RSTRING_LEN(obj), 0, 0, out);
 }
diff --git a/ext/oj/parse.c b/ext/oj/parse.c
index 9094d6a5..992b5253 100644
--- a/ext/oj/parse.c
+++ b/ext/oj/parse.c
@@ -964,10 +964,10 @@ static VALUE protect_parse(VALUE pip) {
 extern int oj_utf8_index;
 
 static void oj_pi_set_input_str(ParseInfo pi, volatile VALUE *inputp) {
-    rb_encoding *enc = rb_to_encoding(rb_obj_encoding(*inputp));
+    rb_encoding *enc = rb_enc_get(*inputp);
 
-    if (rb_utf8_encoding() != enc) {
-        *inputp = rb_str_conv_enc(*inputp, enc, rb_utf8_encoding());
+    if (oj_utf8_encoding != enc) {
+        *inputp = rb_str_conv_enc(*inputp, enc, oj_utf8_encoding);
     }
     pi->json = RSTRING_PTR(*inputp);
     pi->end  = pi->json + RSTRING_LEN(*inputp);