A disk array apparatus of the invention improves the quality of Fiber Channel signals corresponding to mounting positions of disk drives. The disk array apparatus comprises first to fourth groups of a plurality of disk drives each of which stores data; a first data relay device for connecting a first group of a plurality of data transfer paths wired in a direction orthogonally intersecting the row direction and to be connected to the first group of a plurality of disk drives through a first loop-like data transfer path; a second data relay device for connecting a second group of a plurality of data transfer paths wired in a direction orthogonally intersecting the row direction and to be connected to the second group of a plurality of disk drives through a second loop-like data transfer path; a third data relay device for connecting a third group of a plurality of data transfer paths wired in a direction orthogonally intersecting the row direction and to be connected to the third group of a plurality of disk drives through a third loop-like data transfer path; and a fourth data relay device for connecting a fourth group of a plurality of data transfer paths wired in a direction orthogonally intersecting the row direction and to be connected to the fourth group of a plurality of disk drives through a fourth loop-like data transfer path. The first and third relay devices are interposed between the first and third groups of a plurality of disk drives. The second and fourth relay devices are interposed between the second and fourth groups of a plurality of disk drives.