论主合同无效时过错担保人的责任

The Liability of the Faulty Guarantor When the Principal Contract Is Invalid

摘要: 《民法典》第388条规定主合同无效导致担保合同无效，但现行理论与司法实践对无效后法律效果的处置存在逻辑裂隙。应基于法律拟制与信赖保护原则，将担保责任的效力延伸至主合同无效后产生的清算返还之债。这一解释既符合担保的从属性功能，又能避免《担保制度解释》第17条在适用上的混乱。在此基础上需要进一步厘清，主合同无效后，过错担保人实质上承担双重责任：一是基于默示担保对债务人返还义务的清偿责任；二是对担保合同本身无效的缔约过失责任。前者覆盖本金返还等履行利益，后者赔偿信赖利益损失。

Abstract: Article 388 of the Civil Code stipulates that the invalidity of the principal contract renders the guarantee contract invalid. However, existing theories and judicial practices exhibit logical inconsistencies in addressing the legal consequences following invalidity. Based on the principles of legal fiction and protection of legitimate expectations, the validity of the guarantee obligation should extend to the liquidation and restitution obligations arising after the principal contract becomes invalid. This interpretation aligns with the accessory function of security while avoiding confusion in applying Article 17 of the Interpretation on the Security System. Building on this, it is necessary to further clarify that after the invalidity of the principal contract, the negligent guarantor essentially bears dual liabilities: first, the obligation to discharge the debtor’s restitution duty based on implied security; second, liability for pre-contractual fault arising from the invalidity of the guarantee contract itself. The former covers performance interests such as principal repayment, while the latter compensates for losses of reliance interests.