In an image forming apparatus for making a position deviation correction, a position deviation amount can be accurately calculated by stabilizing the detection result at position deviation detecting and considering an ideal correction amount and an actual correction amount to make the position deviation correction accurately. A forming unit forms a pattern for position deviation detection without making the position correction for less than one pixel by an image position correcting unit, to a pattern formed in the vicinity of a detection region of a detecting unit, and the position deviation amount is calculated by using a value of a position correction which is not made to the pattern for position deviation detection to be formed.