PROBLEM TO BE SOLVED : To prevent arrears of rent while securing an opportunity to acquire potential customers. SOLUTION : In response to a request of rental guarantee operation support device 10 for rating a rent payment ability of a tenant with credit monitoring timing, in a residence-changing support device 20, a residence-changing support processing part 202 reads from a sales property management data table 2012 property information about a sales real estate property matching a family size and outputs it as a sales property candidate list with respect to each tenant rated highest in rent payment ability. With respect to each tenant rated otherwise in rent payment ability, when the rent rank of the rental real estate property where he or she currently occupies is equivalent to a higher rank than the rank in rent payment ability, property information about the rental real estate property at the rent rank equivalent to a lower rank than the rank in rent payment ability is read from a rental property management data table 2013 and outputted as a list of residence-changing property candidates. COPYRIGHT : (C)2011, JPO&INPIT