An image forming apparatus transfers pattern images for color deviation detection of the respective colors on an endless belt, and corrects color deviation occurring when each image forming unit forms an image on a recording material, in accordance with the amount of color deviation detected by a registration detection sensor. The image forming apparatus forms pattern images of the respective colors on the endless belt at the intervals determined based on the total variation obtained by totaling each variation of the transfer and detection positions of a pattern image of each color on the endless belt from an ideal position. This enables to reduce color deviation detection errors by using pattern images for color deviation detection and improve the accuracy of color deviation correction.