A control method, for a transaction management server of a transaction administrator administrating commodity transactions between a seller and a buyer, comprises transmitting to a forwarder terminal an instruction to transport a commodity received along with price information of the commodity from a seller terminal; writing the price information into a database; receiving from the forwarder terminal and writing into the database the number of the waybill issued when the commodity is loaded into transportation by the forwarder; transmitting to the seller terminal information indicating that the transaction administrator has made an alternative payment for the commodity; receiving from the forwarder terminal and writing into the database the number of the waybill put on the commodity having arrived at a destination and commodity identification information; receiving the commodity identification information of the commodity delivered to the buyer from the forwarder terminal, and transmitting to a buyer terminal a payment request based on the price information stored in association with the commodity identification information.