Defect management information of a disk apparatus is read efficiently. Pieces of defective track information, which each indicate existence of defective tracks for a group of a plurality of tracks, are stored being associated with physical track numbers. And, pieces of defect information on defective tracks are stored in predetermined groups. Further, pieces of pointer information that indicate start addresses of storage address for the above-mentioned predetermined groups are stored. When a processing means receives an instruction of read or write to a track of a storage medium, the processing means refers to a piece of defective track information based on the above-mentioned addresses. When existence of a defective track is indicated, the processing means refers to a piece of pointer information corresponding to the group relating to the referred piece of defective track information. Then, the processing means sequentially accesses the pieces of defect information from the storage area indicated by the above-mentioned piece of pointer information, to detect a piece of defect information of the track as the object of the instruction. Then, the processing means performs defect processing on the defective track based on the defect information detected.