diff --git a/src/core/vdom/create-element.js b/src/core/vdom/create-element.js
index fd8f853f..adeac2d6 100644
--- a/src/core/vdom/create-element.js
+++ b/src/core/vdom/create-element.js
@@ -132,7 +132,7 @@ function applyNS (vnode, ns, force) {
   if (isDef(vnode.children)) {
     for (let i = 0, l = vnode.children.length; i < l; i++) {
       const child = vnode.children[i]
-      if (isDef(child.tag) && (isUndef(child.ns) || force)) {
+      if (isDef(child.tag) && (isUndef(child.ns) || isTrue(force))) {
         applyNS(child, ns, force)
       }
     }