According to a composition for a photo-alignment film of the present invention, which includes an azo compound and a polymer that exhibits mutual solubility with the azo compound, an adhesion to a substrate, particularly to a plastic substrate, is improved within both a photo-alignment film having a haze of not more than 1 obtained by forming a layer of the above composition for a photo-alignment film on a substrate and subsequently irradiating the layer with light to generate a liquid crystal alignment ability; and an optically anisotropic medium, wherein a layer (A) obtained by irradiating a layer of the above composition for a photo-alignment film with light to generate a liquid crystal alignment ability, and a polymer layer (B) obtained by polymerizing a liquid crystal compound having a polymerizable group in an aligned state generated by the layer (A) are bonded and laminated together by covalent bonds.