To provide a data array storage apparatus capable of storing error information not to lose real time properties and also not to interfere reading/ writing of data when reading/writing the data in real time or continuously from outside.

In the data storage array apparatus comprising a plurality of disk devices having storage regions composing of more than one block and writing or reading striped data and parity data into or from a group composed of blocks of each disk device, at every time of completing of writing, it is decided whether the error information stored in a memory should be written or not into a specified group, according to the decided result, the error information is read out from the memory to write into the specified group.