To obtain an inorganic protecting film by adding fine particles into an oxidized film of a polysilazane coating film, having a reduced coefficient of friction during sliding on the surface of a protecting film, excellent in durability and corrosion resistance.

This inorganic protecting film is obtained by oxidizing a polysilazane coating film formed by coating to give an inorganic oxide film and adding fine particles to the film. The inorganic protecting film containing the fine particles in the inorganic oxide film is formed at least one face of a nonmagnetic substrate to give the objective magnetic recording medium. In the magnetic recording medium, preferably the magnetic layer is preferably a ferromagnetic metal thin film formed by a vacuum film-forming method. The thickness of the inorganic protecting film is ≥3nm and ≤30nm. The fine particles are an inorganic substance and have ≥3 Mohs hardness, ≥5nm and ≤40nm particle diameters, especially ≥5nm and ≤20nm particle diameters. Particles of silica, alumina, zirconia, titania, chromium oxide, carbon black, polystyrene, etc., may be cited as the fine particle material used.