本研究探討吹哨者保護制度對公司、員工與會計師產生之影響。模型結果顯示，完善的吹哨者保護制度可以提升員工的吹哨意願，進而使公司傾向誠實表達；完善的吹哨者保護制度可能增加或減少會計師的審計成本，會計師若預期公司因員工吹哨意願提高而傾向誠實表達，可降低審計成本，惟公司若不實表達且會計師並未經由查核發現時，會因為員工吹哨而產生商譽等重大損失。因此會計師於不同資本規模、客戶數量、事務所文化、員工素質等狀況下，會產生相異之審計成本變化。 / This study discusses the effect of Whistleblower protection system on firms, employees, and external auditors. Results of the models show that, a perfect Whistleblower protection system can motivate employees to blow the whistle and thus make the firm present honestly. A perfect Whistleblower protection system may increase or decrease external auditors’ audit costs. External auditors may decrease audit costs if they expect the firm will present honestly due to the enthusiasm of employees to blow the whistle, while external auditors may increase audit costs if they can’t afford the loss of goodwill when they couldn’t find the misstatement and the employee blowed the whistle. Therefore, external auditors have different changes in audit costs under different conditions, such as capital scale, number of clients, office culture and staff quality.