PROBLEM TO BE SOLVED : To enable a general user to easily learn many pieces of real estate property information to be handled by plural real estate agencies and to obtain the respective properties at a reasonable cost.SOLUTION : This property deal support system is characterized by feature that it is provided with a database server 3 to store the property information regarding properties to be handled by the real estate agencies, first and second servers 4, 5 connected with the data base server, member terminals 1 owned by the real estate agencies and user terminals 2 owned by users, the member terminals are connected with the first server via a closed-communication network N1, also connected with the second server via an open-communication network N2 and the user terminals are connected with the second server via the open-communication network N2.