The Justice function of contract Law

Although ‌ Administration of justice in the contractual relation has been proposed as one of the functions of contemporary contract law, but from an executive point of view, it can be examined whether contract law should play a positive role or can only play the role of preventing injustice. In this article, by descriptive-analytical method, it was proved that due to Necessity of protection of will principle, contract law has a role in preventing injustice. In this regard, although several criteria such as exchange of unequal economic values, dishonest wager, inappropriate terms, undeserved return and advantage, have been proposed to detect injustice, but the criterion of lack of rational purpose or unrasoablness is more appropriate than others because it includes all the above criteria.