In a method of making a magnetic recording medium by causing a flow of vapor obtained by evaporating a magnetic metal deposition material to impinge and deposit on a moving substrate at an oblique angle with respect to the moving substrate, the substrate is moved so that the incident angle of the vapor flow with respect to the substrate continuously changes from the maximum incident angle to the minimum incident angle, and an oxidizing gas is introduced in the vicinity of the substrate and near the maximum incident angle portion or the minimum incident angle portion of the vapor flow during the formation of a thin ferromagnetic film on the substrate. The maximum incident angle is preferably between 60.degree. and 90.degree., and the minimum incident angle between 30.degree. and 75.degree..