An image forming apparatus includes a controller on the apparatus body to control supply of developers from developer containers to the development devices. The controller includes a storage that reads and stores identification information pieces of all the development devices attached to the apparatus body. When any of the development devices is removed from the apparatus body, and thereafter attached at a position where the removal took place, the controller reads an identification information piece of the development device attached at the position, and when the read identification information piece disagrees with an identification information piece of the development device at the position stored, and agrees with an identification information piece of another one of the development devices at another position, the controller determines that the development device is mistakenly attached and prohibits the supply of the corresponding developers.