To provide an electrophotographic photoreceptor containing a charge generating substance that has sensitivity as high as the sensitivity of a titanyl phthalocyanine pigment and having no humidity dependence of the sensitivity, and to provide an image forming apparatus using the photoreceptor.

The electrophotographic photoreceptor has a photosensitive layer on a conductive support, and is characterized in that: the photosensitive layer contains a pigment containing titanyl phthalocyanine and a 2,3-butanediol adduct titanyl phthalocyanine; and a ratio (Abs780/Abs700) of an absorbance (Abs780) at a wavelength of 780 nm to an absorbance (Abs700) at a wavelength of 700 nm, calculated from a reflection spectrum of the photosensitive layer, ranges from 0.80 to 1.10.