To provide an optical disc and a magnetic optical disc that can make accurate recording and reproduction by using a laser beam without large warping even in hostile environments of low/high temperatures, or high aridity/ humidity.

In an optical disc or a magnetic optical disc that has a protective coat 107 on a recording layer 106 on a base plate 101, a top coat layer 110 consisting of a plurality of layers is provided on a reverse surface (optical surface) to suppress the warping. This top coat layer is composed of a transparent inorganic dielectric film 108 and a transparent ultraviolet cured resin film 109. The inorganic dielectric film is 5 to 100 nm thick and the ultraviolet cured film is 1/4 to 4 times as thick as the protective coat layer. Further, refraction factor differences between the inorganic dielectric film and the ultraviolet cured resin film is within ±10% each other, and also within ±10% of that of the base plate.