An image forming apparatus includes an image bearer, an image forming unit, an intermediate transfer member, a secondary transfer member, an image detector, a computing device, and a conveyor device. The computing device calculates a traveling speed of the intermediate transfer member based on detection information provided by the image detector. The conveyor device continuously transports to a secondary transfer portion a plurality of recording media one by one at a predetermined interval between successive recording media. The image forming unit forms a test image at a space between successive recording-medium contact regions of the intermediate transfer member at which the recording medium contacts the intermediate transfer member. A travel distance of the intermediate transfer member from the detection position on the intermediate transfer member to the secondary transfer portion in a traveling direction thereof is shorter than the space between the successive recording-medium contact regions.