To provide an electronic commerce assisting method with which the charge-back risk of electronic commerce by credit sales on a virtual store side can be reduced and an electronic commerce method using it.

The system has an article purchase wisher 6 which can select price payment by a credit card when buying an article by connecting to a virtual store 10 via a communication network 4, the virtual store 10 which requests the article purchase wisher 6 to send personal data regarding the credit card, adds the personal data to a credit confirmation message, and transfers them, and an electronic commerce support center 2 which compares the personal data added to the credit confirmation message with personal data of the genuine bearer of a credit card registered in a database 24 for authentication to generate and transmit authentication assistance data assisting the decision of whether the article purchase wisher 6 is the genuine bearer to the virtual store 6.