The present invention unitarily manages the configuration change of a storage system so as to know the latest configuration, and evaluates the reliability in advance when the configuration is changed so that the generation of a failure is suppressed. When the host 1 is connected to the switch 2, the attribute information of HBA 1A and the attribute information of the switch 2 are stored in the connection information storage unit 2C by FDMI (Fabric Device Management Interface) (S1, S2). Each attribute information is associated with each other and is managed as combination information. The storage device 3 acquires the combination information from the switch 2 (S3, S4), and requests the management device 4 to judge the reliability of this combination (S5). The management device 4 judges the combination of the HBA and the switch (S6), and notifies this judgment result to the storage device 3 (S7). When the configuration of the storage system is changed, the reliability of the configuration can be confirmed before starting operation with the configuration after change, and therefore the generation of a failure can be decreased.