PURPOSE: To transfer the data base to a state of one time point on the way of updating by holding a state of a start time point of a transaction, and a state of two data bases of the latest time point to which updating is applied, in a first storage device, and also, holding a state of the data base of one time point on the way of updating in a second storage device.

CONSTITUTION: At the start time point of some work logical unit, a state 21 of a data base and a state 22 of the data base, and a state 24 of the data base are allowed to coincide entirely, and management information 25 has information related to its coincidence state. Thereafter, when updating is applied to the data base, its updating is reflected on the state 22 of the data base, and also, reflected on the management information 25, as well. In this case, the state 22 of the data base held in a first storage device 23 is copied to the state 24 of the data base of a second storage device 26, and the management information 25 is changed to the state of its one time point. In such a way, the data base can be transferred to the state of one time point on the way of updating, and the data base management processing is improved.