In an information communication system, user personal information is batch-managed in a user management center apparatus. The center apparatus issues temporary information, which includes temporary user information and temporary authentication information, in response to a log-in request from a user terminal apparatus that designates a net-shop apparatus, and sends the information to the user terminal apparatus and the designated net-shop apparatus. Thereby, if the user terminal apparatus sends an authentication request to the net-shop apparatus on the basis of the information, the net-shop apparatus can authenticate the user terminal apparatus on the basis of the information from the user management center apparatus. At this time, the user personal information does not go to the net-shop apparatus, and there is no need for the net-shop apparatus to manage the user personal information.