An image forming apparatus includes a coordinate converter (112) that corrects an image position in one pixel unit by converting a coordinate, a gradation value converter (113) that corrects the image position in less-than-one pixel unit by converting a gradation value, an image outputting unit (121) that forms a detection toner image including an intermediate gradation pixel onto an image bearing member that can bear a toner image, and a light reflection characteristic detector (122) that detects a light reflection characteristic of the detection toner image. The gradation value converter is adjusted in accordance with a detection output of the light reflection characteristic detector.