A photo-detection apparatus includes a light-shielding film, an optically-coupled layer, a photodetector, and an optical system. In the light-shielding film, light-transmitting regions and light-shielding regions are alternately arranged in at least a first direction within a plane. The optically-coupled layer faces the light-shielding film and includes a grating that propagates light in the first direction. The photodetector includes first photo-detection cells and second photo-detection cells arranged on an imaging area. The optical system is disposed between the optically-coupled layer and the photodetector. An image of light transmitted by parts of the optically-coupled layer that face each of the light-transmitting regions and light-shielding regions is enlarged or reduced by the optical system and formed on a corresponding one of the first and second photo-detection cells.