Abstract: The parties concerned including the sales staff or the customer himself/herself can accurately grasp the customer's problem and efficiently provide a service (product) suitable for solving the problem. According to the present invention, the problem organization database 321 is hierarchically connected to at least the problem, the measure to solve the problem, and the service to contribute to the measure. A plurality of problems set in the problem database 321 are displayed to be selectable on the display screen of the sales terminal that can be operated by the parties concerned including the sales staff or the customer himself/herself, and when the plurality of problems displayed on the display screen are selected, the plurality of measures connected to the lower layer of the plurality of problems are displayed, and when the plurality of measures displayed on the display screen are selected, the plurality of selected services connected to the lower layer of the measures are displayed.