Abstract: A payment system includes an information processing apparatus, a sales terminal, and a server that are configured to establish communication with each other. The server includes a member information database that has ID information stored in association with a member ID of a member of the payment system; a member ID receiving unit that receives the member ID from the information processing apparatus; a member identifying unit that refers to the member information database and identifies the member ID associated with the ID information; a sales information transmitting unit that transmits the sales information that has been transmitted from the sales terminal along with the ID information; and a payment processing request unit that receives from the information processing apparatus card information to be used to pay the payment amount indicated in the sales information and transmits a payment processing request including the card information to a financial institution.