To provide a disk array device capable of providing data transfer speed, corresponding to redundant arrays of expensive disk (RAID) 3, even when one of constituting magnetic disk devices is broken down, in a RAID4/5 disk array device.

In this disk array device, corresponding to a read access request from a host computer, data read from respective magnetic disk devices 14 and 15 are successively stored in a data buffer 12 for the unit of a data block and from the time point, when the data for one block from the magnetic disk devices 14 and 15 are completely stored respectively, the stored data are read out of the data buffer 12 in a specified order and transferred to a host interface 19. Then, a disk array control part 11 is provided for concurrently performing the parallel read of data from the magnetic disk devices 14 and 15 and the transfer of data to a host interface 19.