PROBLEM TO BE SOLVED : To provide a real estate rental management system capable of having rent lower than standard without using a public rent assistance institution.SOLUTION : Rent is capable of being lowered than standard even when a public rent assistance institution is not used since a service rent which has discounted from standard rent is set according to an amount of security deposit a tenant 17 deposits to a rent contract management company 14. Thus, even persons who were not able to clear strict constraint conditions such as household income or personnel composition of the tenants in a conventional rent assistance institution are capable of having benefit of discounted rent.COPYRIGHT : (C)2014, JPO&INPIT