diff --git a/lib/inspector.js b/lib/inspector.js
index 43cdd53bf0a4b8..2cd0c191e13ac5 100644
--- a/lib/inspector.js
+++ b/lib/inspector.js
@@ -16,7 +16,7 @@ if (!hasInspector)
 
 const EventEmitter = require('events');
 const { validateString } = require('internal/validators');
-const util = require('util');
+const isFunction = require('internal/util/isFunction');
 const { Connection, open, url } = internalBinding('inspector');
 
 const connectionSymbol = Symbol('connectionProperty');
@@ -68,7 +68,7 @@ class Session extends EventEmitter {
 
   post(method, params, callback) {
     validateString(method, 'method');
-    if (!callback && util.isFunction(params)) {
+    if (!callback && isFunction(params)) {
       callback = params;
       params = null;
     }