An image forming apparatus includes an image forming station for conveying a sheet material along a lateral reference position and for forming an image on the sheet material; refeeding device for refeeding to the image forming station the sheet material on which the image has been formed in the image forming station; means, provided in the sheet refeeding means, for shifting the sheet material in the lateral direction from the lateral reference position by a predetermined amount, wherein the amount of the shift is predetermined on the basis of a change in a lateral dimension of the sheet material resulting from an image forming operation in the image station.