本文分析檢討民法第252條違約金酌減規定之適用對象、規定根據、性質、適用型態及酌減之考慮因素等。本條規定得適用於懲罰性違約金及損害賠償總額預定之違約金。本文認為，此一規定亦得類推適用至依契約約定逕行沒收債務人既已給付之情形；其次，民法第252條規定屬於誠信原則下不被允許之權利行使類型，而且性質上是實體法上之狹義抗辯，即法院得依職權斟酌事實而酌減違約金。但是法院得依職權斟酌事實有別於法院依職權調查事實，即法院得依職權斟酌事實而酌減違約金仍須遵守民事訴訟程序之辯論原則與主張及舉證責任原則。亦即在民事訴訟程序之辯論原則下，所謂實體法上之狹義抗辯，有別於德國民法第343條第1項第1句明定須債務人聲請法院酌減違約金，僅不須債務人在訴訟程序上表示行使權利之意思，因此即使是原告債權人本身之事實陳述得以認定違約金過高，法院亦得依職權斟酌事實而酌減違約金；此一情形，並未違反民事訴訟程序之辯論原則。最高法院大多數判決對本條規定採取法院得職權（斟酌事實）酌減違約金，值得贊同。反之，原告債權人陳述之事實並未能使法院確信違約金過高，債務人訴訟程序上負有主張及舉證責任；債務人應主張或舉證卻不為主張或舉證，或未能使法院獲得違約金過高之確信，應自行承擔不利判決之結果。此外，若干最高法院判決認為酌減違約金須達顯相懸殊或顯失公平之程度始得酌減，亦應予以肯定。最後，為貫徹保護債務人之意旨，判斷違約金是否相當或過高之時點，宜以事實審最後言詞辯論終結時為準。

This paper analyzes some basic issues on the application of Article 252 of the Civil Code which provides that where the ”penalty” agreed is excessively high, the court may reduce it to an appropriate amount. My focus is mainly on the objects, legal foundation, nature and the types of applications, and the factors that should be taken into consideration when a court applies this Article to reduce the agreed penalties or liquidated damages. Most Supreme Court decisions hold that Article 252 of the Civil Code is applicable to both the agreed penalties and liquidated damages. To be more precisely, I suggest that it is an analogue application of Article 252 when it applies to cases where an oblige forfeiture money paid by an obligor before he/she breaches the contract. Further, most Supreme Court decisions take the view that so long as there is a litigation between the obligee and the obligor, the court may ex officio reduce the agreed penalties or liquidated damages and there is no need for the defendant/obligor to request so and it does not matter whether the claimant or the defendant has provided the facts to the court that the agreed penalties or liquidated damages is excessively high. But if there is no fact for the court to take the view that the agreed penalties or liquidated damages are excessively high, the defendant has to present such facts, and if necessary, he must prove them. I take the view that the legal foundation of Article 252 of the Civil Code is the principle of good faith. My point is that even if Article 252 does not in existence, the obligee's right of claim to the agreed penalties or liquidated damages is still subject to the principle of good faith when the agreed penalties or liquidated damages is excessively high in comparison with all possible reasonable interests of the obligee. It is also worth noting that a few Supreme Court decisions also indicate that the agreed penalties or liquidated damages must be excessively high or remarkable unfair in comparison with all possible reasonable interests received by the obligee in case where the obligor had performed his/her obligation. Finally, the court's power to reduce the agreed penalties or liquidated damages should base on all the facts presented by the parties to the litigation before the second instance of the court concludes the proceedings where the parties make their final debate with arguments.