An error table stores information indicating the occurrence of an error. A statistical score addition table stores the number of scores for disk or path according to the error. A control unit adds the first number of scores to the error disk. Also, when the information indicating the occurrence of the error is not stored in the error table, the control unit adds the second number of scores smaller than the first number of scores to the path to the error disk, while when the information is stored, the control unit adds the third number of scores larger than the first number of scores to the path. The control unit separates the path or disk of which the number of scores exceeds a threshold from the disk array apparatus.