PROBLEM TO BE SOLVED : To provide more property information to prospective customers of real estates. SOLUTION : This system is constituted of a server 1 for intermediating real estate deals between a PC 2 that performs processing regarding real estate purchasing and a PC 3 that performs processing regarding real estate selling, and a storage device provided with the server 1. The server 1 receives purchase information including customer-specific information for specifying customer from the PC 2, and when receiving request for reading the purchase information from the PC 3, the server 1 transmits the purchase information to the PC 3.