In continuous printing of plural sheets of recording paper, a controlling section of an image forming apparatus corrects a writing position for a first sheet of recording paper in accordance with an off-center amount detected by a carrying position sensor with respect to the first sheet of recording paper. As for an nth sheet of recording paper, the controlling section corrects the writing position for the nth sheet of recording paper in accordance with an off-center amount alpha(n-1) detected by the carrying position sensor with respect to an (n-1)th sheet of recording paper. In a case where an absolute value of a difference between an off-center amount alphan detected by the carrying position sensor with respect to the nth sheet of recording paper and the off-center amount alpha(n-1) exceeds a threshold, the controlling section corrects the writing position in accordance with the off-center amount alphan and causes an exposure unit to write again the electrostatic latent image at the writing position corrected in accordance with the off-center amount an, instead of writing an electrostatic latent image at the writing position corrected in accordance with the off-center amount alpha(n-1). This makes it possible to minimize a decrease in printing speed and improve accuracy of a position with which an image is formed on a sheet of recording paper.