PURPOSE: To improve anti-corrosiveness and weathering by providing a transparent dielectric layer comprising a specified compound one side or both sides of an magneto-optical recording layer.

CONSTITUTION: Dielectric layers 2a and 2b comprising a mixture of aluminum nitride and boron nitride are arranged on one side or both sides of a magneto- optical recording layer 3. As the mixture is stable chemically as compared with the conventional single aluminum nitride, a large protecting action is obtained with respect to the magneto-optical recording layer. In addition, as a refractive index becomes large, a large action of amplifying an angle of rotation of a polarized light is noted as caused by a Kerr effect.