diff --git a/src/shrpx_http2_upstream.cc b/src/shrpx_http2_upstream.cc
index 919cdb9e..c6b72a15 100644
--- a/src/shrpx_http2_upstream.cc
+++ b/src/shrpx_http2_upstream.cc
@@ -466,7 +466,9 @@ void Http2Upstream::start_downstream(Downstream *downstream) {
 void Http2Upstream::initiate_downstream(Downstream *downstream) {
   int rv;
 
+#ifdef HAVE_MRUBY
   DownstreamConnection *dconn_ptr;
+#endif // HAVE_MRUBY
 
   for (;;) {
     auto dconn = handler_->get_downstream_connection(rv, downstream);
diff --git a/src/shrpx_http3_upstream.cc b/src/shrpx_http3_upstream.cc
index 8ebecbf5..02255d63 100644
--- a/src/shrpx_http3_upstream.cc
+++ b/src/shrpx_http3_upstream.cc
@@ -2347,7 +2347,9 @@ void Http3Upstream::start_downstream(Downstream *downstream) {
 void Http3Upstream::initiate_downstream(Downstream *downstream) {
   int rv;
 
+#ifdef HAVE_MRUBY
   DownstreamConnection *dconn_ptr;
+#endif // HAVE_MRUBY
 
   for (;;) {
     auto dconn = handler_->get_downstream_connection(rv, downstream);
diff --git a/src/shrpx_https_upstream.cc b/src/shrpx_https_upstream.cc
index bf7bf114..210c0c5b 100644
--- a/src/shrpx_https_upstream.cc
+++ b/src/shrpx_https_upstream.cc
@@ -463,7 +463,9 @@ int htp_hdrs_completecb(llhttp_t *htp) {
     return 0;
   }
 
+#ifdef HAVE_MRUBY
   DownstreamConnection *dconn_ptr;
+#endif // HAVE_MRUBY
 
   for (;;) {
     auto dconn = handler->get_downstream_connection(rv, downstream);