diff --git a/packages/input-number/src/input-number.vue b/packages/input-number/src/input-number.vue
index 1d2294ca7a5..71aebd7a43c 100644
--- a/packages/input-number/src/input-number.vue
+++ b/packages/input-number/src/input-number.vue
@@ -168,7 +168,7 @@
         return this.size || this._elFormItemSize || (this.$ELEMENT || {}).size;
       },
       inputNumberDisabled() {
-        return this.disabled || (this.elForm || {}).disabled;
+        return this.disabled || !!(this.elForm || {}).disabled;
       },
       displayValue() {
         if (this.userInput !== null) {