An image capturing apparatus comprises an image sensor on which a plurality of pixels are two-dimensionally arranged, and which has a plurality of image forming pixels and a plurality of types of focus detecting pixels that are discretely arranged among the plurality of image forming pixels and respectively have different distributions of received light, and selection means for, when the plurality of pixels are read out from the image sensor while thinning out the plurality of pixels, selecting one thinning-out read-out mode from a plurality of thinning-out read-out modes having different thinning-out phases of the plurality of pixels, wherein the plurality of types of focus detecting pixels are arranged so that in each thinning-out read-out mode, only signals of the focus detecting pixels of one type of focus detecting pixels are read out, and signals of the focus detecting pixels of other types are not read out.