A storage apparatus is capable of relocating volumes accurately even when a plurality of storage apparatuses are connected. The storage apparatus comprises an external connection function for recognizing an external logical volume set on a physical storage device as a logical volume inside the storage apparatus, a storage control device with a volume relocation function for relocating the logical volumes based on set conditions, and a storage unit with a plurality of physical storage devices. When the host sends a read request to the logical volume set on the physical storage device of the storage unit, the volume relocation function generates internally the same read request to the external storage volume set on the physical storage device in the external storage apparatus and relocates volumes based on the monitor information obtained by monitoring responses to the read request.