There is provided an optical recording medium, in which a light transmitting
layer is formed on a disc substrate, having less deflection and being excellent
in recording/reproducing properties. In an optical disc, an information signal
area on which an information signal can be recorded and/or reproduced is formed
on a major surface of a disc substrate thereof; a light transmitting layer which
can transmit a laser beam used in a process for recording and/or reproducing the
information signal is formed on a side on which the information signal area is
present; and a clamp reference plane is arranged on a major surface of the light
transmitting layer in a clamp region. If the optical disc is clamped by a chucking
unit of a drive, it is clamped by making the clamp reference plane on the major
surface of the light transmitting layer contact with a mounting surface of a table
for mounting the disc, and making a magnetic metal plate contact with the major
surface of the disc substrate, and then sandwiching the optical disc between.
