Provide is an electrophotographic photoreceptor exhibiting excellent evenness of halftone images together with fine line reproduction, and an image forming method thereof, as to a photoreceptor in which an oxytitanium phthalocyanine pigment having a maximum diffraction peak at a Bragg angle (2θ±0.2°) of 27.2° in CuKα X-ray diffraction. Also disclosed is an electrophotographic photoreceptor possessing a body having cylindrical conductive support provided thereon photosensitive layer containing oxytitanium phthalocyanine pigment having maximum diffraction peak at a Bragg angle (2θ±0.2°) of 27.2° in CuKα X-ray diffraction, and flanges jointed at both ends of the body, wherein at least one of flanges is fitted with driving shaft having drive hole having at least 3 sides, and a ratio B/A of cross-sectional area B of engaging part of rotation shaft to rotate the electrophotographic photoreceptor with respect to cross-sectional area A of the drive hole is 0.890-0.998.