A disk array device and a method of supplying power to a disk array device to which power is supplied by at least two AC inputs are provided. Where at least two AC/DC power-supply groups are provided in correspondence with each of the AC inputs and each AC/DC power-supply group includes at least two AC/DC power supplies that are connected to the AC input corresponding to that group, outputs from the AC/DC power supplies are summed separately for each group to obtain group total outputs for each group, and the group total outputs are input to each of a plurality of loads in the disk array device to provide power to each of the loads.