An image forming apparatus includes a photosensitive body (11) having a charge transport layer (11d) as a surface layer. The charge transport layer (11d) as the surface layer is charged and exposed so that a latent image is formed thereon. In order to form a basic dot whose diameter is from 10 .mu.m to 25 .mu.m, a thickness t (.mu.m) of the charge transport layer (11d) and a diameter D (.mu.m) of the basic dot satisfy the relationship of t.ltoreq.D/2.