A novel electrophotographic photoreceptor is disclosed, comprising an undercoating layer provided on an electrically conductive substrate having thereon a light-sensitive layer, wherein the undercoating layer is obtained by coating a solution of a composition comprising zirconium and silicon or a solution of a mixture of a zirconium acetyl acetonate compound and a silane coupling agent, the silicon content in the composition comprising zirconium and silicon is in the range of 5 to 35 mol % based on the total amount of zirconium and silicon, and the hardened undercoating layer obtained from the zirconium acetyl acetonate compound and silane coupling agent is a layer having a hardening degree of 1.2 or less.