A real estate affairs support system for realizing efficient affairs when real estate agents of a franchise system are established comprises an information providing terminal provided in an alliance agent, enabling retrieval of real estate object information, and capable of outputting an object slip containing alliance agent identification information and real estate object information, a system center server, and contractor agent computer provided in a contractor agent, enabling input of the alliance agent identification information, client information, and real estate object information, capable of transmitting the alliance agent identification information, client information, and real estate object information to the system center server, and receiving contract data from the system center server to print the data. The system center server correlates the alliance agent identification information, real estate object identification information, identification information about the contractor agent attending to the client, and identification information about the real estate dealing with one another, stores the information in a storage, shares the predetermined commission with the alliance agent and the contractor agent correlated with the identification information about the real estate dealing when payment of the contract money by the client is inputted.