The lock construction portion of a storage system receives, from a host 101 or SVP, the number of hosts which is the number of hosts 101 actually connected to the storage system, and the number of groups which is the number of storage device groups among a plurality of storage device groups 301 for which access exclusion control must be performed. Based on the received number of hosts and number of groups, the lock construction portion controls for which storage device groups to provide control blocks, and the number of control sub-blocks to provide in different control blocks.