A virtual tape apparatus is interposed between a host and a tape device so as to store data transmitted from the host to a logical tape volume. The virtual tape apparatus includes: a data communication unit that receives data transmitted from the host; a RAID device having a logical tape volume for storing the data; a management table that manages attribute information of data stored in the physical tape volume; a position determination section that determines the write starting position of the data stored in the logical tape volume on the physical tape volume based on the management table; and a drive control unit that writes data in the logical tape volume to the physical tape volume based on a result of the determination.