Electrophotographic photoreceptor, process cartridge, and image forming apparatus

To provide an electrophotographic photoreceptor that is excellent in charge maintainability, prevents the occurrence of leakage current caused by sticking of foreign substances, and prevents an increase in residual potential generated when repeated images are formed.SOLUTION: An electrophotographic photoreceptor comprises: a conductive substrate; an undercoat layer arranged on the conductive substrate; and a photosensitive layer arranged on the undercoat layer. The undercoat layer has a thickness of 1 μm or more and 10 μm or less, and contains at least one type of perinone compound selected from the group consisting of a compound represented by a specific formula (1) and a compound represented by a specific formula (2), at least one type of metal oxide particles selected from the group consisting of aluminum oxide particles, iron oxide particles, copper oxide particles, magnesium oxide particles, calcium oxide particles, and silicon dioxide particles, and a binder resin.SELECTED DRAWING: None