The change of rental rates unilaterally has become a common issue. This change can be detrimental to one of the parties entering into the lease agreement. In Islamic law, every transaction that harms one party is not allowed, because every muamalah transaction must prioritize the value of justice, it must not take the rights of others. This study is intended to provide an explanation of how the unilateral rental rates changes after the stipulation and agreement on the lease agreement in the perspective of ijarah. This research is a normative juridical research with a concept approach, a case approach, and a law approach. The data collection techniques were obtained from primary data in the form of legal materials and secondary data taken from cases relating to changes in rental prices. The legal theory used as an analytical knife in this research is the theory of justice, the theory of contracts and the theory of dispute resolution. The results of this study state that unilateral changes in the rental prices on lease agreement are not allowed, in the concept of an ijarah contract, an action that harm one party are strictly prohibited. Regarding the object being leased, it must be clear regarding the time (period) of the lease, the form of the benefits being leased and also the ujrah (reward/wages) that must be paid.