Patent ID: 7817523

Claim:
A recording medium comprising: a first recording layer including a first data area into which data is recorded, a first calibration area which is placed on an inner side of the first data area and a third calibration area which is placed on an outer side of the first data area; and a second recording layer including a second data area into which data is recorded, a second calibration area which is placed on an inner side of the second data area and a fourth calibration area which is placed on an outer side of the second data area, wherein an edge on an other side, which is different from an one side, of the second calibration area is located at a position obtained by shifting to the one side at least by a tolerance length from an area portion in said second recording layer corresponding to an edge on the one side of the first calibration area, in a radial direction of the first recording layer or the second recording layer, in which the tolerance length indicates an acceptable range of a relative position shift between an address which is defined on the predetermined position in said first recording layer and an address which is related to the predetermined position in said second recording layer, an edge on the other side of the fourth calibration area is located at a position obtained by shifting to the one side at least by the tolerance length from an area portion in said second recording layer corresponding to an edge on the one side of the third calibration area, in a radial direction of the first recording layer or the second recording layer.