Proposed are a storage apparatus and its control method capable of restoring data of a virtual page to an appropriate device hierarchy according to its data value. This storage apparatus stores, in a backup-destination storage medium, data stored in the respective physical pages allocated with the virtual volume and management information of the virtual volume including information concerning the device hierarchy to which the respective physical pages belong according to a backup command of the virtual volume, and allocates a physical page of the same device hierarchy as the device hierarchy of the physical page that was allocated before the backup to each of the restoration-target virtual pages of the virtual volume, respectively, and writes corresponding data, which was read from the storage medium, into each of the allocated physical pages according to a restoration command of the virtual volume and based on the management information of the virtual volume stored in the storage medium.