To obtain a management method securing uniqueness in a distributed system of estimated/real calculation information.

An estimated/real calculation management processing 102 receiving a use request retrieves an estimated/real calculation management database 103, and when the estimated/real calculation information for a use requesting user exists, its use is permitted. When the information does not exist, each computer system is requested to transmit user's estimated/real calculation information. When the information is retrieved as the result of the request, the information is transmitted to the processing 102, which permits the use requesting user to use the information. After the completion of use of the information by the user, the processing 102 judges whether the information is transmitted from another computer or not, and when the information is transmitted form another computer, returns the information to the transmitting estimated/ real calculation management processing and updates an estimated/real calculation management database by the use of the information.