In an exclusive lock management in common to both the In-Band and the Out-of-band, a lock control technique of a storage system capable of removing the factor that may cause the discrepancy in the configuration information in a disk array system is disclosed. In the storage system, a shared memory in a DKC of a storage subsystem has lock management information for uniformly managing the operation authority for the configuration information in the shared memory that is used in common by both the channels of the host terminals and the management client terminals, and a CPU in the DKC gives the operation authority for changing the configuration information to either the host machine or the management client based on the lock management information in the shared memory in response to an access request from the host terminals or the management client terminals.