A data recording/reproducing apparatus in which plural disc-shaped recording/reproducing means are run in parallel. The apparatus is designed for avoiding the risk of the write/readout unit being changed in size to lower the transfer rate to raise the cost brought about by changing the number of the disc-shaped recording/reproducing means. A disc array unit 11 accesses video data of 163840 bytes equal to 40 times as many as 4096 bytes and audio data of 8192 bytes equal to twice as many as 4096 bytes to a data driving unit 11D made up of seven HDDs with a size of, for example, 3584 bytes. An accessing control unit 12 controls data accessing to the disc array unit 11. A data adjustment unit 25 appends a volume of nonsensical data (padding data) equal to a multiple of 3584 bytes at the time of recording, while taking out data excluding the padding data during reproduction in terms of 4096 bytes as a unit.