An image forming apparatus having a photosensitive member, an image forming device which forms an image by forming an electrostatic latent image on the photosensitive member and developing the electrostatic latent image in accordance with an image forming condition, a copy number detector for counting the number of images formed by the image forming device, a first control program for correcting the image forming condition in accordance with a correction value whenever a predetermined number is counted by the copy number detector, a second control program for manually regulating the image forming condition corrected by the first control program, a memory for storing the image forming condition regulated by the second control program, and a third control program for revising the correction value in accordance with the image forming condition stored by the memory.