Electrophotographic photoreceptor

An electrophotographic photoreceptor, which is removably installed and used in a device main unit of an electrophotography application device so as to form a process cartridge, the device main unit including a driving-side power transmission portion, the electrophotographic photoreceptor comprising:

• a photosensitive drum including a cylindrical conductive base having an outer peripheral face that has a photosensitive layer containing a photoconductive material;
• and
• a flange, which is fitted to an end portion of the photosensitive drum, including a driven-side driving force transmission portion, the flange transmitting, to the photosensitive drum, a rotational driving force from the driving-side power transmission portion with the driven-side driving force transmission portion, the driven-side driving force transmission portion having
• a cylindrical member protruding from a face of the flange that is disposed on a side of the flange that receives the rotational driving force, a center of the cylindrical member being disposed on a central axis of the photosensitive drum, and
• engaging protrusions which are disposed parallel to the central axis at positions on the outer periphery of the cylindrical member that trisect the cylindrical member, each protrusion protruding in a radial direction and engaging the driving-side power transmission portion.