PROBLEM TO BE SOLVED : To provide a real estate lease managing device which enables a lessor to efficiently secure a new tenant without making a depreciation term long and also making the tenant stay for a long time and meanwhile, enables the tenant to enjoy benefits that the tenant pays only a low-cost rent as a whole by continuing to stay for a long time.SOLUTION : If a points increasing/decreasing part of the real estate lease managing device detects rent payment, the part specifies a tenant, reads the ' acquired points Px' of the tenant, reads ' imparted points Pb to rent' , adds the ' imparted points Pb to rent' to the ' aquired points Px' , and writes addition results as ' acquired points Px' to a tenant database (S121 to S125). The points increasing/decreasing part reads ' accomplishment points Po' of the rental and compares the ' acquired points Px' with the ' accomplishment points Po' (S126 and S127). As a result of the comparison, if the ' acquired points Px' reaches the ' accomplishment points Po' (Yes in S127), ' 1' representing free rent is set in a ' free rent tag' of a tenant database 170 (S128).