An image forming apparatus includes a plurality of forming devices, a measuring device and a correcting device. In execution of a steady-deviation detection, the correcting device controls the forming devices to form a first pattern and detects a steady deviation amount of the image forming position on a basis of a measurement result of the first pattern. In execution of a varying-deviation detection, the correcting device controls at least one of the forming devices to form a second pattern and detects a varying deviation amount of the image forming position having a cycle on a basis of a measurement result of the second pattern. The correcting device determines necessity of executing the other one of the steady-deviation detection and the varying-deviation detection on the basis of the measurement result in the one of the steady-deviation detection and the varying-deviation detection.