diff --git a/lib/config-generator.js b/lib/config-generator.js
index c202cfc2..b9f91479 100644
--- a/lib/config-generator.js
+++ b/lib/config-generator.js
@@ -68,7 +68,8 @@ class ConfigGenerator {
         if (this.webpackConfig.useDevServer() &&
             (
                 devServerConfig.https
-                || (devServerConfig.server && devServerConfig.server.type === 'https')
+                || devServerConfig.server === 'https'
+                || (typeof devServerConfig.server === 'object' && devServerConfig.server.type === 'https')
                 || this.webpackConfig.runtimeConfig.devServerHttps
             )) {
             this.webpackConfig.runtimeConfig.devServerFinalIsHttps = true;