减损义务规定在我国《合同法》第119条中:当事人一方违约后,对方应当采取积极的措施防止损失的扩大;没有采取适当措施致使损失扩大的,不得就扩大的损失要求赔偿。当事人因防止损失的扩大而支出的合理费用,由违约方承担。减损义务适用于缔约过失情形吗?笔者认为,减损义务来源于诚实信用原则,而诚实信用原则作为《民法通则》的一项基本原则,贯穿于整个民法领域。因此,减损义务也应适用于缔约过失情形。进一步说,减损义务不但适用于合同关系,同样也应当适用于民事法律行为和事实行为等整个民法领域。其理由有三: Article 119 of the “Contract Law” in our country: After one party breaches a contract, the other party shall take active measures to prevent the loss from expanding; if no appropriate measures are taken to cause the loss to increase, no compensation shall be required for the expanded loss. The reasonable expenses incurred by the parties for preventing the increase of losses shall be borne by the defaulting party. Impairment obligations apply to contracting negligence do? In my opinion, the derogation obligation comes from the principle of good faith, and the principle of good faith as a “general rule of civil law,” a basic principle throughout the entire field of civil law. Therefore, the derogation obligation should also apply to the fault of the contracting party. Furthermore, the obligation of derogation applies not only to contractual relations but also to the entire civil law field, such as civil legal acts and de facto acts. There are three reasons for this: