A perpendicular magnetic storage medium in which a perpendicular magnetic anisotropic film having an easy magnetization axis perpendicular to the plane thereof is formed on a substrate, wherein the perpendicular magnetic anisotropic film is a film of a sub-oxide of Fe-Co alloy, the sub-oxide has a half-value width not less than 0.7 degrees with respect to a diffracted X-ray peak caused by oxide phase observed in X-ray diffraction spectrum, and saturation magnetization in terms of 4.pi.Ms of the film is within a range from 6,000 Gauss to 13,000 Gauss. The medium has high recording/reproducing sensitivity, high recording density and high wear resistance, and can be produced easily and economically at a low substrate temperature.