A focus detection apparatus performs focus detection by a phase difference method using an image pickup element including first and second pixels, the focus detection apparatus includes a correlation data calculator which calculates correlation data between pixel data obtained from the first pixels and the second pixels in ranges of image data, a detector which detects a saturated pixel having a level of at least a predetermined value in each of the ranges, an adding processor which performs an addition processing of the correlation data calculated in each of the ranges based on a detection result, and a defocus amount calculator which calculates a defocus amount based on a result of the addition processing, and the adding processor performs the addition processing using correlation data obtained from a first range in which the number of the saturated pixels is less than a predetermined number.