A storage system has a management computer and a storage device, where the storage device is connected to an external storage device and includes a first processor, a storage medium on which a plurality of logical storage devices is based, and a plurality of ports. The management computer includes a memory and a second processor, the memory storing port information, path information between host and storage device indicating the association between a host computer and the plurality of logical storage devices and ports, and path information between storage devices indicating the association between the external storage device and the plurality of logical storage devices and ports. The second processor executes band accommodation processing on either a path between host and storage device or a path between storage devices on the basis of the port information, the path information between host and storage device, and the path information between storage devices.