To form a normal image even if distortion such as bending occurs on an intermediate transfer belt.

In the image forming apparatus 100 equipped with an intermediate transfer device 160 where an endless intermediate transfer belt 164 is arranged adjacently to an image forming part 150, a toner pattern is formed at a predetermined position on the intermediate transfer belt 164 by the image forming part 150 when image forming is finished, and a position of the formed toner pattern is detected by photosensors 210 and 220 in a case where next image forming is performed, a bending position of the transfer belt when the apparatus is stopped is calculated from the detected position of the toner pattern, and transfer timing to the transfer belt is changed so as to perform image forming at a position other than the calculated bending position of the transfer belt when next image forming is performed.