The object of the present invention is to provide a system for evaluating the customer equity of products and services provided by a company, with consideration of customer-purchase trends, and to provide a means for evaluating the ratio of repeat customers and the customer-equity growth ratio by store, region, and/or customer group, and to provide data for establishing an optimal plan for increasing sales. A system 100 for evaluating customer equity according to the present invention comprises a computer system 2 for conducting sales management for a company, and an evaluation computer 10 connected to the computer system 2 via a communications line 5. The evaluation computer 10 comprises a Web server 11, a communications controller 15, an application server 12, and a database 14 for recording purchase records received from a company or store. The database comprises a table of original records 14a for recording purchase records in the order that they are generated, a master table of customers 14b, and a tabulation table 14c for sorting records by time period. The application server 12 comprises a purchase-data collecting means 12a, a customer-equity sorting means 12b, and a customer-equity evaluation means 12c. The customer-equity evaluation means 12c comprises a total-customer-equity tabulating means 12c-1; an average-customer-equity tabulating means 12c-2; a means of tabulating the customer-stability ratio 12c-3; and a customer-equity growth-ratio tabulating means 12c-4.