An information recording medium of the present invention includes N information
layers on a substrate (1), where N is an integer of 2 or more. Information is recorded / reproduced by irradiating each of the information
layers (11, 12) with a
laser beam (4). When the N information
layers are referred to as a first
information layer to an N-th
information layer sequentially from the opposite side to a
laser beam incident side, the L-th
information layer included in the N information layers includes at least a
recording layer (135) capable of undergoing a
phase change through
laser beam
irradiation, a
reflective layer (132), and a
transmittance adjusting layer (131) in this order from the laser beam incident side, where L is an integer satisfying 2≦L≦N. The
transmittance adjusting layer (131) 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. In the
transmittance adjusting layer (131), the content of Nb is at least 2.9 atom %.