An image sensor includes: a plurality of imaging pixels; and a plurality of focus detection pixels constituted with a micro-lens and a photoelectric conversion element that receives a focus detection light flux transmitted through a photographic optical system and executes photoelectric conversion. The photoelectric conversion element in each of the focus detection pixels includes a light-receiving area where the focus detection light flux is received; light-receiving area images corresponding to each of the focus detection pixels are each formed as the light-receiving area is projected via the micro-lens onto a pupil plane of the photographic optical system; and a positional relationship of the micro-lens and the light-receiving area is determined in correspondence to an image height so that the light-receiving area images corresponding to all the focus detection pixels are superimposed on one another on the pupil plane.