The present invention relates to an image forming apparatus comprising a main image forming mechanism (20) for forming a toner image on a recording sheet (40) based on image information and an auxiliary image forming mechanism (30) for forming an auxiliary image on a recording sheet (40) on which the main image is formed. The auxiliary image forming mechanism (30) supplies charged toner to a substrate provided with a plurality of toner passages holes and selectively forms electric potential which allow or does not allow the charged toner to pass through each toner passage hole by a pair of electrodes. A predetermined image is formed with the toner passed through the toner passage holes.