PROBLEM TO BE SOLVED : To enable a person who wants to purchase a real estate or a lease wisher to easily view and survey an object and also to receive real estate mediation with small commission.SOLUTION : A computer system 11 manages information about objects desired to be sold and objects desired to be leased as objects desired to be sold information and objects desired to be leased information respectively, and if a terminal device 13-1 to 13-N accesses the computer system through the Internet and inputs a preregistered member password, the computer system allows real estate mediation. The computer system retrieves real estate objects coinciding with desired conditions given from the terminal device to display the real estate objects as real estate objects on the terminal device. If mediation is established in accordance with the real estate object information, a commission that is predetermined uniformly is collected. In the case of acquiring a member password, a terminal device desires a registration including predetermined necessary information and pays a preregulated admission charge, the computer system issues/registers a member password.