PROBLEM TO BE SOLVED : To provide a real estate brokerage business support system capable of reducing business of a real estate agent from stock registration of a rental to moving out of a tenant.SOLUTION : A central control center 13 provides business support information including page allocation information for preparing magazine publishing data to each real estate brokerage business support device 11, it receives magazine publishing information from each real estate brokerage business support device 11, and it carries out publishing business of an advertisement magazine for rentals. The real estate brokerage business support device 11 supports the work from stock registration of the rental managed by the real estate agent to moving out of the tenant. A stock managing means 24 registers information of the rental in a mediation managing database 19, a sales support means 25 supports introduction of the rental in stock to customers, a work support means 26 supports mediation work of a rental agreement for the rental in stock, and a management support means 27 supports management of the rental after concluding the agreement.