An image forming apparatus includes a photosensitive member, a developing portion to develop an electrostatic image on the photosensitive member, and a sensor to detect a toner image formed by the developing portion to output density information depending on a toner amount per unit area. A controller controls a supply of developer on the basis of a detection result of a supply control toner image. The controller adjusts an exposure condition for forming the supply control toner image by the exposure portion after exchange of the photosensitive member on the basis of first information and second information. The first information is a detection result when a first control toner image, formed before an exchange of the photosensitive member, is detected by the sensor, and the second information is a detection result when a second control toner image, formed after the exchange of the photosensitive member, is detected by the sensor.