To eliminate the risk of loss of points by the loss of a point card and outflow of personal information by dispensing with the carrying of the point card or the like by a purchaser.

This sales information management method is used when a mobile terminal owner purchases a commodity/service based on commodity/service information transmitted to the mobile terminal through the Internet. (a) A management server transmits the commodity/service information to the mobile terminal through the Internet. (b) The mobile terminal transmits its terminal ID information to the member-side terminal of a seller when the mobile terminal owner purchases the commodity/service. (c) The member-side terminal of the seller transmits the terminal ID information of the mobile terminal and sales information to the management server. (d) The management server accumulates the sales result, and transmits discount information to the member-side terminal of the seller. (e) The seller performs the sales by use of this discount information.