According to one embodiment, an image forming apparatus includes an image carrier, a image forming unit, a measurement unit and a controller. The image carrier includes a central region on which a target image as an object of an image forming is formed and a peripheral region placed outward of the central region. The image forming unit forms a reference image on the peripheral region and the central region, before the image forming is started. Also, the image forming unit forms the target image on the central region based on a preset condition and a third reference image on the peripheral region, during the image forming. The measurement unit measures a physical quantity for the reference images.