A disk array apparatus including a rack-shaped basic frame, and a plurality of disk boxes that can be inserted into and pulled out of the basic frame depth-wise. Each disk box has: disk drive connectors for connecting a plurality of disk drives arranged in a matrix on a platter substrate, which is the bottom face of the disk box, roughly parallel to the depth direction of the basic frame; and a cooling module for cooling the disk drives. The disk box is a hermetically sealed structure.