An image forming apparatus forms a color image by superimposing images formed in a plurality of colors. To prevent color deviations from occurring in the image forming apparatus, a predetermined registration pattern is formed in each of the plurality of colors, and an image forming position is adjusted for each color in accordance with a detection result given by a detecting unit on detecting the predetermined registration pattern. A value of a parameter having an effect on an output of the detecting unit is set for each color so that the value set for at least one of the colors is different to the values respectively set for other colors. The value of the predetermined parameter may be set as a fixed value for each color. Alternatively, the value of the predetermined parameter may be a variable that is automatically set.