PROBLEM TO BE SOLVED : To improve the satisfaction degrees of both of a supplier and an intermediator and to increase a real estate supply by making a latent supplier exist clearly so as to construct a fiduciary relation between with the intermediator. SOLUTION : In an intermediating server, a member registering part 421 registers a member, a receiving part 422 of information on persons desiring to sell/operate real estate receives information on real estate being the object of selling/operating from a supplier (a selecting device of a real estate company and rent managing company) 401 and/or information on a desired condition for selling/operating the real estate, a storage part 423 stores the received information, a transmission part 424 of information on persons desiring to sell/operate real estate transmits all or a part of the information stored by the part 423 to the intermediator (a retrieving device of persons desiring to sell/operate real estate) 403 based on a reading request from the intermediator 403.