民法債編通則之債務不履行規定，採過失責任為歸責原則，並分為給付不能、給付遲延及不完全給付，且賦與債權人請求履行、請求賠償及解除契約等救濟手段。民法債編分則另有瑕疵擔保規定，以買賣及承攬之物之瑕疵擔保，實務上最為重要。為解決債務不履行與瑕疵擔保之競合關係，最高法院民事庭會議作有重要決議。民法之債務不履行及瑕疵擔保規定，係繼受舊德國民法及瑞士債務法。鑑於德國債法已經大幅修改，且國際契約法亦有新構想，臺灣債法未來發展，應如何因應，亟待深思。

This paper, focusing on the breach of contract, elaborates the developments of the structure of non-performance under Taiwan Civil Code. The core of the elaboration include reception of foreign law and the developments of the domestic scholarly theories and court decisions.