A technique is provided in which, even when the number of devices and device addresses handled in the storage apparatus side increases, it is possible to access all the devices and save used resources by simple control of the configuration definition information without adding the device addresses retained on the host side. The host side handles a virtual device for an access to an actual device handled on a storage apparatus side to retain a virtual device address, specifies an actual device to be mounted to the virtual device, and makes an access for data input/output by the virtual device address. A CHA of a controller maps an actual device address to a virtual device address and retains it in a table in a SM, and when receiving the access by the virtual device address, obtains the corresponding actual device address from the table to access the actual device.