An image forming apparatus comprises: attach/detach sections to/from each of which a developer container for containing developer can be attached/detached; an image bearing body for bearing a latent image; and a displaying section for displaying information thereon. When developer containers are attached to the attach/detach sections, the apparatus is usable as a color image forming apparatus for forming a color image by developing the latent image bore on the image bearing body with the developer in each developer container. When a developer container is attached to only one attach/detach section, the apparatus is usable as a single-color image forming apparatus for forming a single-color image by developing the latent image bore on the image bearing body with the developer in the developer container. Information displayed on the displaying section when the apparatus is used as the color image forming apparatus is different from information displayed on the displaying section when it is used as the single-color image forming apparatus.