本研究以代理問題、自我申辯及道德發展來探討決策者之承諾續擴行為。採用實驗法及受試者間問卷設計，以上市櫃財務部門經理人員共91位及會計研究所學生共105位為受試者，分別進行三因數變異數分析。研究結果顯示，受試者在有自利動機且資訊不對稱情況下，持續進行方案程度會大於無自利動機或沒有資訊不對稱。但兩種受試者在自我申辯條件下不具顯著水準，表示受試者雖然在資本支出決策前有自行設置資金成本率，但當方案之回饋訊息低於心中之預期目標時，兩種受試者不會因此明確及可靠的訊息低於心中的預期目標而降低對執行方案的續擴程度。當決策者道德發展水準高時，代理問題情境之強弱對持續進行方案決策傾向有顯著差異，但在低道德發展水準之決策者的決策傾向會因為代理問題情境之強弱具有顯著差異，亦即在有誘因及私有資訊者比未具備者較會傾向持續進行利已但不利於公司之方案。最後僅財務部門經理人員，雖然在資本支出決策前有自行設置資金成本率的情況下，仍會受較強之代理問題情境影響產生自利動機繼續無經濟價值之方案；另外低道德發展水準之財務部門經理人員，會因為資本支出前無自行設置資金成本率，使心中缺乏一個預期目標，因此較容易忽略負面之回饋訊息而產生自我申辯繼續無經濟價值之方案。 Managers commonly face the problem of deciding whether to continue committing resources to a risky and highly uncertain project, or possibly personal commitment and reputation, have already been spent. This study examines the effect of agency problem, self-justification and moral reasoning on the level of escalation of commitment in investment decisions. Experiment is a 2 (agency problem) by 2 (self-justification condition) by 2 (moral reasoning levels) between-subjects design, to explore the escalation of commitment, and to analyze the influence of the agency problem (with/without), self-justification condition (with/without) and moral reasoning levels (high/low) on the escalation of commitment.Results from 91 listed and OTC firms’ financial manager and 105 graduated students. The findings suggested that agency problem had strong explanatory power for project escalation of commitment. Subjects are likely to continue a project that is expected to be unprofitable only when adverse selection conditions are present. The relationship between moral reasoning levels and agency problem can accurately describe the tendency to escalate commitment. While financial manager with lower moral reasoning level showed a significant stronger tendency to continue a failing project when adverse conditions emerged. Investment decisions of financial manager were analyzed and a significantly interaction was found between agency problem and self justification. While financial manager with self justification situation showed a significant stronger tendency to continue a failing project when adverse condition.