This specification discloses an electrophotographic apparatus for forming an image by digital processing improved in a gradation property, provided with image data processing means for processing input image data to the apparatus body into data for forming an electrostatic latent image, electrostatic latent image forming means for effecting image exposure by digital optical means conforming to the electrostatic latent image data to thereby form the electrostatic latent image on the electrophotographic photosensitive member, and developing means for developing the electrostatic latent image with a toner to thereby form a developed image, wherein the image data processing means effects an image calculation taking into account the mutual action around a pixel constituting the electrostatic latent image in conformity with the size of the pixel when it processes the input image data into the electrostatic latent image data.