An image forming apparatus includes an image forming unit configured to form measurement images used for density correction at different timings using pseudo halftone processing patterns and a density detection sensor for detecting density of an object to be detected on an optical path including the formed measurement image. Further, the image forming apparatus includes a shutter which is arranged in the optical path between a density detection sensor and the measurement image, changed, by a motor, to a closed state in which a detecting surface of the density detection sensor is closed when the measurement image is not detected, and changed to an open state in which the detecting surface of the density detection sensor is opened when the measurement image is detected. Further, the image forming apparatus includes a controller which changes an image forming condition based on the detection result of the density detection sensor.