A novel electrophotographic photoreceptor comprising an electrically-conductive substrate having provided thereon an undercoat layer and a photoconductive layer in thin order, wherein the undercoat layer is formed by using a high molecular weight compound having an alkoxysilyl group; a high molecular weight compound having an alkoxysilyl group, and an organic metal compound; or a high molecular weight compound having an alkoxysilyl group, an organic metal compound and a silane coupling agent. As the organic metal compound there may be preferably used at least one selected from the group consisting of an organic zirconium compound and an organic titanium compound.