External audit is the not the part of internal control.The internal audit can suggest improvement in internal check system. The external audit can not suggest improvement in internal check system. The internal audit can perform his duties under the terms of appointment. The management can limit the scope of work at any time. The external auditor can perform his work to terms of appointment and other prescribed law. The scope is very wide. Internal audit is an employee of the company. He is not an independent person. External auditor is not an employee of the company.