An image forming apparatus of this invention includes an image forming position correction unit which corrects an inclination or curve of an image in the main scanning direction by converting coordinates designating pixel positions of a bitmap image in the sub-scanning direction. It is discriminated whether image formation is normal image formation or formation of the toner image for detection by an image forming condition correction unit. Based on the discrimination result, the image forming apparatus is controlled so as to correct the image forming position by using the image forming position correction unit in a case in which the image formation is discriminated as the normal image formation, but so as not to correct the image forming position by using the image forming position correction unit in a case in which the image formation is discriminated as formation of the toner image for detection.