An image forming apparatus includes: medium transporting belt that carried an image recording medium on its surface, and is driven so that the surface is circulatively turned; a plural number of toner image forming drums facing the transporting belt, each including an image bearing surface having an electrostatic latent image formed thereon, a developing unit for developing the electrostatic latent image into a toner image, and an image transferring unit for transferring the toner image on the transporting belt or an image recording medium held on the transporting belt; medium supplying trays and path for successively supplying image recording media to the transporting belt; a medium attracting electrode facing the transporting belt; a counter electrode opposing to the medium attracting electrode with respect to the medium attracting electrode; an electric field formed between the medium attracting and counter electrodes to cause the transporting belt to attract the image recording medium to the transporting belt; and control unit that controls voltage applied from a power source between the medium attracting and counter electrodes so that electric field developed therebetween when the image recording medium is not interposed therebetween is weaker than an electric field developed therebetween when the image recording medium is interposed therebetween, and has such a direction as to cause the transporting belt to attract the toner to the transporting belt.