Abstract: A disk array device comprises: a hard disk drive module including a disk for recording information thereon and having one side that has a length substantially equal to the diameter of the disk; a battery module; an operation module; a fan module having at least one cooling fan; a controller module having a controller; a power supply module provided for supplying power to the modules; a circuit board to which the above-mentioned modules are connected via electrical connectors; and a substantially box-shaped chassis in which the modules and the circuit board are housed. A front surface and a rear surface of the chassis are opened in a rectangular shape. A length of one side of the opened front surface of the chassis is substantially the same length as the one side of the hard disk drive module.