Abstract: An image forming apparatus includes an image carrier and a developing device to develop a latent image formed on the image carrier by applying two-component developer, including toner, onto the latent image. The developing device includes a developing part containing the two-component developer and a developer stirring device to stir the two-component developer. A toner supplying device supplies toner to the developing part of the developing device, and a toner density detection device detects a toner density of the two-component developer in the developing device. A toner control device calculates a difference between an output value VT of the toner density detection device and a criterion value VTref for controlling the toner density of the two-component developer and controls the toner supplying device based upon the difference.