An image transferring and recording medium conveying device for an image forming apparatus of the present invention includes a belt (11) forming a nip (N) for image transfer between it and an image carrier (W) and conveying a recording medium (P) via the nip to thereby transfer a toner image formed on the image carrier to the recording medium. A bias applying device applies a bias for image transfer to the nip. Assume that an image transfer bias Tb is applied during a leading edge interval in which the leading edge portion of the recording medium between the leading edge and a preselected position in the direction of medium conveyance moves away from the nip, and that an image transfer bias Ta is applied to the nip during a remaining interval in which the remaining portion of the recording medium moves away from the nip. Then, a controller switches the image transfer bias Tb within a range lower than the image transfer bias Ta.