An image forming apparatus of this invention is provided with a conveying guide that is curved in the direction reverse to the curved shape of a nip portion of a fixing unit in order for leading sheet paper that is vertically conveyed at the time of fixing in the horizontal direction and the top of the curved portion of the conveying guide is constructed with a guide belt. The contacting force of the curl correction unit with the guide belt of the curl correction unit is adjusted according to amount of curl of sheet paper produced at the time of fixing and corrects the curve of sheet paper properly.