PROBLEM TO BE SOLVED : To construct a real estate deal intermediation system enabling the discount of an intermediation fee to both a seller and a buyer, and capable of clearing effect to cost to a real estate agent.SOLUTION : This system manages access conditions to a property advertisement bulletin board, a communication service provision part 144 in the system feeds a response to real estate information sent via the Web back to a sender of the real estate information, and the system mediates a real estate deal among the seller, the buyer and the real estate deal agent on the basis of the fed-back information. A new scheme intended for persons of ' the seller' and ' the buyer' who are principals of the real estate deal, and ' the real estate agent' who intermediates between them, converting needs in each position into a mutual advantage to the persons in other positions is developed on the Web.