An image forming apparatus includes an image bearing member configured to carry an image, a developing device configured to develop a latent image with a developer including toner and carrier, and a toner content sensor configured to detect a ratio of the toner to the developer in the developing device. A toner container contains the toner to be supplied to the developing device, and a notifying portion notifies necessity for exchange of the toner container when the ratio indicated by the output of the sensor reaches a set level lower than the predetermined range. A controller controls an image forming condition so as to change, on the basis of the output of the toner content sensor, a development contrast wherein the controller sets the development contrast at a level higher than that when the ratio is in the predetermined range, at least in part of a period from when the ratio indicated by the output of the toner content sensor becomes lower than the predetermined range to when the ratio indicated by the output of the toner content sensor reaches a first set level.