To enable a seller of contents to easily search for a selling destination, to sell the contents at proper prices and to enable a purchaser of the contents to select the contents to be purchased among many contents.

A contents selling member transmits the contents intended to be sold and desired selling conditions of them from a selling member terminal 1-i to an intermediary server 3. The intermediary server 3 stores the transmitted contents and simultaneously transmits the contents to the respective purchasing member terminals 2-1 to 2-m. Contents purchasing member of the purchasing member terminals 2-1 to 2-m transmit the desired purchasing conditions to the intermediary server 3 when they want to purchase the contents. The intermediary server 3 determines candidates for closing bid according to the desired selling conditions, the purchasing desired conditions from the respective persons who desire purchase and predetermined rules and informs the selling member terminal 1-i of them. The contents selling member determines the selling destination of the contents among the candidates for the closing bid.