To obtain a volume image of a given generation. A storage system of this invention includes a disk device in which an original volume is provided to read/write data from a host, a copy volume is provided to store a copy of the original volume of a predetermined timing, and a snapshot volume is provided to store snapshot data of a snapshot of the original volume; and a storage control unit which includes a management unit for controlling the storage control unit, a channel I/F connected to the host, and a device I/F connected to the disk device, in which the management unit copies data of the original volume to the copy volume at a predetermined timing, stores the snapshot data of the snapshot in the snapshot volume corresponding to a write request in the original volume, manages a generation of the created snapshot and a generation of the copy volume, and reads data from at least one of the snapshot volume and the copy volume when a read request from a volume of a generation different from that of the original volume is received from the host.