An apparatus includes a photosensitive member on which an electrostatic latent image is formed, a developing unit that develops the electrostatic latent image as an image by using toner, an image bearing member to which the image is transferred, a detecting unit including a plurality of light-emitting elements that emit light toward the image bearing member and a light-receiving element that receives light reflected from a detection target, and a control unit that adjusts an image forming condition. The control unit adjusts a light-emission ratio between the light-emitting elements based on a difference between a reflected light amount at a first position on the image bearing member and a reflected light amount at a second position.