本文採取隨機方向距離函數方法，探討制度變革前、後(第一次金融改革)對台灣銀行業技術效率的影響。資料期間涵蓋1999年至2012年。相較傳統Shephard距離函數，隨機方向距離函數方法最大優點係可同時考量增加意欲產出、減少投入與非意欲產出。本文依循Koutsomanoli-Filippaki et al. (2009a) 模型，並納入考慮非意欲產出。本文採取隨機邊界法進行實證估計，以最大概似法估計方向距離函數，依據Battese and Coelli (1995)的模型將環境變數納入實證模型 (主要模型)，並考量未包含環境變數之模型，與主要模型比較。此外，為凸顯非意欲產出之重要性，本文亦估計未考慮非意欲產出之模型以及傳統距離函數，以茲比較。 實證結果顯示，考慮非意欲產出與環境變數的主要模型，其估計結果相較其他模型之無效率明顯高估。2002年以前，技術無效率逐漸攀升。一次金改期間，技術無效率明顯下降，證明制度變革下，銀行效率獲得改善。惟2004年後反轉向上，尤其在雙卡風暴與次貸風暴期間，技術無效率明顯惡化。此外，本文將資料分群進行分析，發現公營銀行或是金控銀行較有效率。 / This paper aims to gain further insights into whether the policy of First Financial Restructuring (FFR) does improve the technical efficiency of banks in Taiwan during the period 1999-2012 by using the directional technology distance function (DDF). Compared to the conventional distance function, DDF simultaneously allows for the expansion of the desirables and the contraction of the undesirables. We follow Koutsomanoli-Filippaki et al. (2009a), and differing from them, we include undesirable outputs in DDF to depict a bank’s true production activities. We find on average that the banks have a lower technical inefficiency with the main model compared to the other models. However, prior to 2002, the technical inefficiency exhibits a gradual upward trend and then posts a downward trend during the FFR period. These results suggest that the improved efficiency in the FFR period is possibly due to enhanced banking and benefits obtained from compliance with FFR. After the FFR period, the inefficiency scores deteriorate sharply, especially during the “credit card and cash card crisis” in 2006 and “the subprime mortgage crisis” in 2008. Public banks are more efficient than private banks. Banks belonging to a financial holding company (FHC) may operate more efficiently than those belonging to a non-FHC.