An optical information recording medium having two or more information layers,
wherein the irradiation of either the information layer with a laser beam converging
thereon causes information signals to be recorded or reproduced; the nearer positioned
information layer than the farthest information layer as viewed from the incidence
side of the laser beam has a recording layer varying between two optically detectable
states, and
where Tc is the transmittance of the nearer positioned information
layer when the recording layer is in state (a) and Ta, the transmittance,
when it is in state (b). This makes possible accurate accurately recording and
reproduction of information onto and out of the farther information layer irrespective
of whether or not any information is recorded on the nearer information layer.
