Patent ID: 8088464

Claim:
An information recording medium, comprising N information layers provided on a substrate, where N is an integer of 2 or more, each of the information layers being irradiated with a laser beam and thereby information being recorded/reproduced with respect to each of the information layers, wherein with the N information layers being referred to as a first information layer to an N-th information layer sequentially from an opposite side to a laser beam incident side, an L-th information layer included in the N information layers includes at least a recording layer capable of undergoing a phase change through irradiation with a laser beam, a reflective layer, and a transmittance adjusting layer in this order from the laser beam incident side, where L is an integer satisfying 2≦L≦N, and the transmittance adjusting layer contains Nb, oxygen (O), and at least one element M selected from Ti, Zr, Hf, Y, Cr, Zn, Ga, Co, Bi, In, Ta, and Ce, and the content of Nb in the transmittance adjusting layer is at least 2.9 atom % but not more than 26.5 atom %.