Exercising integral management of storage apparatuses even when SANs are integrated or when the scale of a SAN expands. In response to an operation request from a management terminal, an integrated management computer collects the management information for storage apparatuses from management computers; selects, based on the collected management information, one or more management computers, to which the task of performing the requested operation is to be assigned; provides the selected management computer(s) with the ability to manage the storage apparatuses which are the management target for the management computer(s); collects pieces of process information from the management computer(s) with the management ability; and integrates and manages the collected pieces of process information.