To provide a business support system which can easily retrieve and display the customers residing in every liaison area and can improve the liaison activity efficiency.

A client 2 receives the retrieved customer information from a server 1 and divides this information in every administration unit and address to display them as the check buttons together with a retrieval button. Then the client 2 turns on the optional one of check buttons and pushes the retrieval button to output a retrieval request to the server 1 with the administration unit and address which are shown by the pushed retrieval button used as keys. The server 1 retrieves the customer information via the relevant key and sends this retrieved information to the client 2 to display it there.