To make credit card payment without informing a credit card member store being a commodity supplier of individual information such as credit card number, name and the address of purchaser in on-line shopping using a computer network.

A user 1 designates a precontracted credit card company 3 when making the credit card payment on a web page of the credit card member store 2. Then, a page transfers to the web page of the credit card company 3, and the credit card is certified on this web page. A server of the credit card company 3 issues identification information when certifying the credit card, and informs the credit card member store 2 of the identification information. The credit card member store 2 controls by relating the identification information to a commodity. The credit card company 3 receives the commodity, and sends the commodity to the user 1 side from the identification information and the individual information of the user 1.