本文利用可以同時捕捉到銀行增加意欲產出、減少投入與減少非意欲產出的方向距離函數，評估台灣銀行業與個別銀行在民國93年至97年的無效率值與生產力變化。設定逾期放款為銀行生產放款時的非意欲產出，以考量銀行的放款品質，也考慮到銀行都會付出成本來提供服務給存戶，因此以交易性存款作為銀行提供服務的替代變數，使銀行的服務包含在效率評估內，並以固定的方向向量作為無效率值加總的基礎，來衡量台灣整體銀行業的無效率。實證結果是台灣銀行業的無效率值隨著雙卡風暴的遠去，有逐年遞減的趨勢，生產力的變化則是退步的情況較多。 / In this paper we estimate Taiwanese banks’ efficiency and productivity change during 2004-2008. The estimates are derived from the directional distance function. We treat non-performing loans as an undesirable output arising from the production of loans to measure the quality of loans. Considering every bank would make costs to serve customers, we choose transaction deposits as an alternative variable to capture the service provided by banks. The way we set the directional vector allows the aggregation of individual bank inefficiency and productivity change to the industry level. Our findings indicate that inefficiencies of Taiwanese banking industry were decreasing after the over of credit and cash card debts. And Taiwanese banking industry experienced productivity regress during this period.