PROBLEM TO BE SOLVED : To provide a system capable of quickly getting a new tenant and reducing a vacancy factor.SOLUTION : This lease transaction support system is provided with a level setting means 302 receiving setting of a rent level of real estate to be lent, a bidding information receipt means 303 receiving bidding information input by a user requiring lease of the real estate to be lent, a candidate information creation means 304 selecting bidding information satisfying the rent level set in the level setting means 302 for creating information about a user as a possible candidate of a tenant and information about the rent presented by the user, a candidate information output means 305 outputting the candidate information created by the candidate information creation means 304, and a proper level estimation means 306 estimating a proper level of the real estate rent from data about the rent in the bidding information received until a certain time. After the certain time, bidding information is selected according to a new level of a rent decided by referring to the proper level, and based on the selected bidding information, candidate information is created to be outputted.