The present invention provides a software storage unit, a backup method, and a backup control program capable of completing data transfer to a data backup destination in a shorter time. The software storage unit includes a software storage section constructed across a plurality of physical machines and a switch section coupled to an external network, wherein the software storage section grasps data to back up, among stored data, which is to be transferred to a data backup destination, splits the grasped data into a plurality of data parts, and issues a command to transfer the split data parts from respective ones of the plurality of physical machines to the data backup destination via the switch section.