INFORMATION RECORDING MEDIUM

摘要

A disk-like information recording medium (8) includes recording areas provided in both of a groove portion (3) and a land portion (4). The information recording medium is divided into groups of a plurality of areas, each track (3, 4) is divided into circular arc-shaped sectors (1) having the same central angle arranged to be radial in the radius direction, identification information (2) is provided at every sector, each track is divided into groups in such a manner that lengths of the circular arc-shaped sectors (1) become almost constant among the groups, and the groove portion and the land portion are wobbled in the radius direction of the information recording medium. When the groove portion information track (3) and the land portion information track (4) which are the recording portions are wobbled in the radius direction, position information can be reliably obtained from the recording portions, and hence recorded information can be accessed reliably. Also, an accuracy with which the rotation of the information recording medium is controlled can be raised, and it becomes possible to position recorded information accurately.