The enclosure 10 in which the storage control system 600 is constructed comprises a scale-out NAS head group 111 constituted by two or more NAS heads, and a scale-up NAS head 110H that is a higher performance NAS head than each of NAS head members 110L that are the NAS heads constituting the scale-out NAS group 111. The enclosure 10 permits insertion into general-purpose slots 104 in which the NAS head members 110L and another type of channel control unit 112 that differs from the NAS head members 110L are inserted. The scale-up NAS head 110H is mounted within the enclosure 10 in a different location from the general-purpose slots 104.