An electronic business transaction system of a trading card typically uses the Internet. That is, when a site for the electronic business transaction of the trading card is accessed over the Internet from a user terminal, a server makes the user terminal display a card pack selecting screen. When a user selects a card pack on the screen, the server makes the user input personal information of the user and a payment method through the user terminal. Thereafter, the server makes the user terminal display a contents confirmation screen so as to make the user select a card pack that the user wants to confirm the contents. When the user selects the card pack that the user wants to confirm the contents by operating the user terminal, the server makes the user terminal display at least a part of illustrations (contents) of cards enclosed in the card pack that the user determines to purchase.