A method of forming an inorganic alignment film is provided comprising a first milling step of irradiating ion beams to a surface of a base substrate, on which the inorganic alignment film is to be formed, from a direction inclined at a predetermined angle .theta..sub.a with respect to a direction orthogonal to the surface of the base substrate, a film-forming step of forming a film made substantially of an inorganic material on the base substrate to which the ion beams are irradiated, and a second milling step of irradiating ion beams to a surface of the film from a direction inclined at a predetermined angle .theta..sub.b with respect to the direction orthogonal to the surface of the film.