It is an imaging element in which pixels which are photoelectric conversion elements are placed at respective square lattice positions, in which, when, in a predetermined region where pixels of the imaging element are placed, a plurality of pairs are arranged in a first line which is any one line among lines and a second line which is parallel to the first line, each pair having pair pixels which are first and second phase difference detection pixels placed adjacent to each other to detect a phase difference among the pixels of the imaging element, the pairs in the first line are placed to be spaced apart from each other by at least two pixels, and the pairs in the second line are placed at positions, which correspond to positions where the pair pixels in the first line are spaced apart from each other.