民法上同時履行抗辯權之研究

於一般私法活動領域，以當事人間債權債務的交換給付為大宗，為確保雙方義務履行的公平，亟需仰賴同時履行抗辯權加以實現。同時履行抗辯權的法理基礎導源於誠信原則，透過保留自己給付之方式作為他方不履行義務之擔保，同時發揮督促他方如實履行給付的心理強制。其以當事人間具有對價關係的債權債務為規範對象，換言之，係以給付義務的牽連關係為核心要件。因此，雖民法的編纂體系將同時履行抗辯權劃歸雙務契約之效力，然只要給付義務間具備實質的牽連關係，縱非本於雙務契約，仍可存在拒絕給付的正當依據，而有類推適用民法第264條之可能。又抗辯權人之對待給付「請求權」受有限制者，原則上並不損及本於債權債務關係所生之牽連關係，故對同時履行抗辯權亦不生影響。其次，同時履行抗辯權既係植基於誠信原則，則其行使亦當不能違反誠信原則，此觀民法第264條第2項之條文規範自明。是故，學說上即有認為，倘抗辯權人嚴正表示不為債務之履行，致使當事人之契約目的顯然無法達成，如仍容許其為同時履行抗辯權的主張，乃違反禁反言原則、背於誠實信用，於此情形應否定其拒絕給付之權能。再者，實務法院經由裁判的累積，逐漸開展出所謂「相當之限制」，藉以限縮同時履行抗辯權的效力範圍，惟此一概念並未見於法律規範之中，其意義內涵、論理基礎、法律效果，均有進一步分析檢討之必要。此外，我國民法係採相對牽連主義，對於履行上之牽連關係係以抗辯權的模式加以規制。通說見解強調抗辯權旨在對抗請求之效力，不生法律關係之改變，與形成權究有不同，其權利行使具有被動性，必以他方當事人的請求為要件。然本文認為抗辯權不僅止於請求之對抗，而是根本性地限制他方債權的請求力，解放自己所負債務之責任，形成不為給付的正當法律地位。本質上乃廣義之形成權，得由抗辯權人主動行使。據此，本文認為同時履行抗辯權所生之阻止請求實現、排除遲延責任、抵銷禁止等法律效果，均以抗辯權人的積極主張為必要，並考量抗辯權的防禦性與永久性，宜解為其法律效果乃向後發生。

關鍵字

同時履行；抗辯權；牽連關係；誠信原則；被動性

並列摘要

The Most common type of activity on private law is the exchange of obligations between parties. In order to ensure the fairness of the both sides, which relies on the exception of simultaneous performing to realize. The legal foundations of the exception of simultaneous performing is on basis of the principle of good faith. Through the way by retaining self-owned prestation as the guarantees while the other party have yet to perform the counter prestation. Meanwhile, it can cause the psychological coercion to urge the other party to perform the counter prestation. The normative object of the exception of simultaneous performing is consideration relationship. In other words, the relationship of obligations is the crucial cornerstone for the exception of simultaneous performing. Therefore, although according to the compilation of Civil Code, the exception of simultaneous performing is categorized as the effect of bilateral contract, but if the obligations come with substantive relationship, which even aren’t base on bilateral contract, still can be a justified basis for refusing to perform. Thus, Article 264 of Civil Code may be applied by analogy to this situation. Moreover, the relationship between obligations is impervious to the restriction of claim, which bases on the counter prestation of exception holder. Accordingly, the exception of simultaneous performing is not influenced by the restriction of claim. Besides, the principle of good faith is the foundation for exception of simultaneous performing, so the exercise of the exception of simultaneous performing should not against the principle of good faith. It is indeed self-evident by the provision of paragraph 2 of Article 264 of Civil Code. As a result, scholars consider that the exception holder solemnly refuses to perform the obligation then cause the outcome of not achieving the purpose of contract, who still able to keep the exception of simultaneous performing, which will breach the principle of estoppel and the principle of good faith. Therefore, it must deprive the right of exception holder in this situation. In addition, court practices develop a concept of “reasonable limitation” by accumulating of cases to constrain the effective scope of the exception of simultaneous performing. However, the definition of the concept of “reasonable limitation” is not provisioned by Civil Code, neither are the keystone and the effectiveness, which are necessary to review and analyze. Furthermore, under the relative relationship doctrine of Civil Code, by means of exception to regulate the relationship between obligations. The general opinion emphasizes that the function of exception is to against the effectiveness of demand, which doesn't alter the legal relationship so that it is different from the right of formation. Thus, the exercise of exception is passive, which on the premise that the other party demands for the satisfaction of the claim. Nevertheless, this study regard that the function of exception is more than the rivalry with demand. Instead, exception fundamentally restricts the right of claim, which liberates the responsibility of exception holder and establishes the legal status of non-performance. In essence, exception is a kind of formation right, can be exercised initiatively. As a consequence, this study consider that no matter what kind of the effectiveness, such as to block the realization of claim, to remove the responsibility of default in performance or to prohibit the exercise of offset, the exception of simultaneous performing takes effect only when the exception holder exercises the right. Additionally, taking into account the defensiveness and the permanency of the exception of simultaneous performing, the effectiveness is properly interpreted as taking effect backward.