In an image forming apparatus that forms an electrostatic latent image for detection on a photosensitive member by light irradiation and performs color-misregistration correction control on the basis of detection of a change in detection current due to the detecting electrostatic latent image passing through a processing unit disposed close to the periphery of the photosensitive member, the intensity of at least one of the apply voltage of the processing unit and the output of the light irradiation unit is set higher than that during normal image formation.