To provide a sales support system capable of providing up-to-date information processed by an existing external processing system to a terminal device used by a customer, and carrying out an information exchanging process between the terminal device and the external processing system.

The sales support system is composed so that service information request data to the external processing system is prepared in a predetermined format in response to a request from the terminal device, the format of the prepared service information request data is converted into a format that can be processed by the external processing system, service information provided from the external processing system in response to the service information request data is converted into the predetermined format, and the service information converted into the predetermined format is provided to the requesting terminal device.