diff --git a/integration-tests/nghttpx_http1_test.go b/integration-tests/nghttpx_http1_test.go
index bbb62227..c99e9364 100644
--- a/integration-tests/nghttpx_http1_test.go
+++ b/integration-tests/nghttpx_http1_test.go
@@ -533,6 +533,49 @@ func TestH1H1RespPhaseReturn(t *testing.T) {
 	}
 }
 
+// TestH1H1HTTPSRedirect tests that the request to the backend which
+// requires TLS is redirected to https URI.
+func TestH1H1HTTPSRedirect(t *testing.T) {
+	st := newServerTester([]string{"--redirect-if-not-tls"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		name: "TestH1H1HTTPSRedirect",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+
+	if got, want := res.status, 308; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+	if got, want := res.header.Get("location"), "https://127.0.0.1/"; got != want {
+		t.Errorf("location: %v; want %v", got, want)
+	}
+}
+
+// TestH1H1HTTPSRedirectPort tests that the request to the backend
+// which requires TLS is redirected to https URI with given port.
+func TestH1H1HTTPSRedirectPort(t *testing.T) {
+	st := newServerTester([]string{"--redirect-if-not-tls", "--redirect-https-port=8443"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http1(requestParam{
+		path: "/foo?bar",
+		name: "TestH1H1HTTPSRedirectPort",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http1() = %v", err)
+	}
+
+	if got, want := res.status, 308; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+	if got, want := res.header.Get("location"), "https://127.0.0.1:8443/foo?bar"; got != want {
+		t.Errorf("location: %v; want %v", got, want)
+	}
+}
+
 // // TestH1H2ConnectFailure tests that server handles the situation that
 // // connection attempt to HTTP/2 backend failed.
 // func TestH1H2ConnectFailure(t *testing.T) {
diff --git a/integration-tests/nghttpx_http2_test.go b/integration-tests/nghttpx_http2_test.go
index fd3bc417..c2920802 100644
--- a/integration-tests/nghttpx_http2_test.go
+++ b/integration-tests/nghttpx_http2_test.go
@@ -1405,6 +1405,49 @@ func TestH2H1DNS(t *testing.T) {
 	}
 }
 
+// TestH2H1HTTPSRedirect tests that the request to the backend which
+// requires TLS is redirected to https URI.
+func TestH2H1HTTPSRedirect(t *testing.T) {
+	st := newServerTester([]string{"--redirect-if-not-tls"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		name: "TestH2H1HTTPSRedirect",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 308; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+	if got, want := res.header.Get("location"), "https://127.0.0.1/"; got != want {
+		t.Errorf("location: %v; want %v", got, want)
+	}
+}
+
+// TestH2H1HTTPSRedirectPort tests that the request to the backend
+// which requires TLS is redirected to https URI with given port.
+func TestH2H1HTTPSRedirectPort(t *testing.T) {
+	st := newServerTester([]string{"--redirect-if-not-tls", "--redirect-https-port=8443"}, t, noopHandler)
+	defer st.Close()
+
+	res, err := st.http2(requestParam{
+		path: "/foo?bar",
+		name: "TestH2H1HTTPSRedirectPort",
+	})
+	if err != nil {
+		t.Fatalf("Error st.http2() = %v", err)
+	}
+
+	if got, want := res.status, 308; got != want {
+		t.Errorf("status = %v; want %v", got, want)
+	}
+	if got, want := res.header.Get("location"), "https://127.0.0.1:8443/foo?bar"; got != want {
+		t.Errorf("location: %v; want %v", got, want)
+	}
+}
+
 // TestH2H1GracefulShutdown tests graceful shutdown.
 func TestH2H1GracefulShutdown(t *testing.T) {
 	st := newServerTester(nil, t, noopHandler)
diff --git a/integration-tests/server_tester.go b/integration-tests/server_tester.go
index 868fb6ba..75185907 100644
--- a/integration-tests/server_tester.go
+++ b/integration-tests/server_tester.go
@@ -101,10 +101,8 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 
 	args := []string{}
 
-	backendTLS := false
-	dns := false
-	externalDNS := false
-	acceptProxyProtocol := false
+	var backendTLS, dns, externalDNS, acceptProxyProtocol, redirectIfNotTLS bool
+
 	for _, k := range src_args {
 		switch k {
 		case "--http2-bridge":
@@ -116,6 +114,8 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 			externalDNS = true
 		case "--accept-proxy-protocol":
 			acceptProxyProtocol = true
+		case "--redirect-if-not-tls":
+			redirectIfNotTLS = true
 		default:
 			args = append(args, k)
 		}
@@ -164,6 +164,10 @@ func newServerTesterInternal(src_args []string, t *testing.T, handler http.Handl
 		b += ";dns"
 	}
 
+	if redirectIfNotTLS {
+		b += ";redirect-if-not-tls"
+	}
+
 	noTLS := ";no-tls"
 	if frontendTLS {
 		noTLS = ""