diff --git a/packages/@vue/cli-plugin-unit-mocha/index.js b/packages/@vue/cli-plugin-unit-mocha/index.js
index 2fd61f9a12..1769be92a9 100644
--- a/packages/@vue/cli-plugin-unit-mocha/index.js
+++ b/packages/@vue/cli-plugin-unit-mocha/index.js
@@ -37,9 +37,17 @@ module.exports = api => {
       `https://sysgears.github.io/mochapack/docs/installation/cli-usage.html`
     )
   }, (args, rawArgv) => {
-    const inspectPos = rawArgv.indexOf('--inspect-brk')
+    const inspectStringPrefix = '--inspect-brk'
+    const matchedInspectArg = rawArgv.filter((value) => {
+      return (value.substring(0, inspectStringPrefix.length) === inspectStringPrefix)
+    })
+
     let nodeArgs = []
-    if (inspectPos !== -1) {
+
+    let inspectArg = ''
+    if (matchedInspectArg.length !== 0) {
+      inspectArg = matchedInspectArg[0]
+      const inspectPos = rawArgv.indexOf(inspectArg)
       nodeArgs = rawArgv.splice(inspectPos, inspectPos + 1)
     }
     // for @vue/babel-preset-app <= v4.0.0-rc.7