A color image forming apparatus is described. The color image forming apparatus may includes: a belt that travels in a prescribed direction; a plurality of image carriers arranged in parallel in the prescribed direction, and opposed to the belt and carrying developing agent images of different colors respectively; a backup roller arranged in opposed relation to the belt; a cleaning roller arranged in opposed relation to the backup roller with the belt sandwiched therebetween, and adsorbing an adherent to the belt by a potential difference produced between the backup roller and the cleaning roller; and a discharge member opposed to the belt between a position more downstream in the prescribed direction than a position where the cleaning roller is opposed to the belt and a position more upstream in the prescribed direction than a position where the image carrier arranged on the most upstream side in the prescribed direction is opposed to the belt, for discharging the belt.