A recording medium supplied from any one of paper supply units is printed by an image forming section, and then, the image-formed recording medium is transported via a transport path which is formed along a vertical direction, and thereafter is ejected to an ejection unit which is provided at an upper portion of an image forming apparatus main body. While a developing apparatus of a process cartridge owns a developer storage space, a latent image writing position "P" of an image carrier optically written by an optical writing apparatus is located lower than at least a portion of this developer storage space, and a space defined between the paper supply unit 18a and the optical writing apparatus is made small.