Log information concerning an electronic transaction performed between a transaction device and a business connection server through a network is compared with information concerning a predetermined business connection down-loaded from the server, and the log information is recorded in an IC card accepted by the transaction device when the log information is related to the information concerning a predetermined business connection. Predetermined commodity information is provided to a user in accordance with a request by the user of the IC card when the log information stored in the IC card satisfies a predetermined condition.