德國對於民法債編之全面修正，已經自二○○二年元旦起正式施行，且在為數眾多的領域中，對於德國過去的法制進行了相當大幅度之改革，並有深遠的影響。本文首先闡述德國民法債編修正之緣由，首先為來自國際間之影響，此包括聯合國國際商品買賣契約條約、國際統一私法中心之國際商業契約原則、歐洲契約法原則、正在研擬中的歐洲民法典及一九九二年荷蘭民法典，以及將歐體消費性商品買賣指令轉換為內國法等原因。本文並對於新修正之德國民法債編總論中債務不履行法制基礎原理詳加介紹，並對於統一的「義務之違反」之概念、個別債務不履行之態樣及其法律效果加以分析。於新修正之債編總論中，債務人「義務之違反」成為統一的上位概念。故而，各種債務下履行之態樣，也就是：「給付不能」、「給付遲延」、「瑕疵給付」、「積極侵害債權」與「締約上之過失」，在此統一的「義務之違反」概念下，這些個別債務不履行態樣概念間之區別，原則上都將變的無關緊要。契約法在各個法制序之中，彼此間已逐漸調和靠攏，而此一國際間之發展，值得我們加以注意。

　　　　　On I January 2002 the Amendment of the German Civil Code (BGB), the book of the law of obligations, came into force. In many aspects this reform has a great influence on the German civil law. The background of this reform is mentioned. This is: the influence from the United Nations Convention on Contracts for the International Sale of Goods, Unidroit Principles of International Commercial Contracts, Principles of European Contract Law, Study Group on a European Civil Code, the new Dutch Civil Code and EC Directives. As for the non-performance of obligations, the German legislators use a new unitary concept, i.e. the violation of obligations, in the general part of the law of obligations, § 280 para. I sentence 1 German Civil Code. Therefore, the distinction between each kind of failure in the performance, e.g. impossibility, delay, defects, the positive violation of contractual duty or liability in precontractual negotiations, does not matter any more in principle under this new unitary concept. The contract laws in each legal system comes much nearer than before. Such an international development deserves our attention,