A light-receiving device of the present disclosure includes a light-trapping sheet, and a photoelectric conversion section optically coupled thereto. The light-trapping sheet includes: a light-transmitting sheet; and a plurality of light-coupling structures arranged in an inner portion of the light-transmitting sheet. The light-coupling structure includes first, second and third light-transmitting layers. A refractive index of the first and second light-transmitting layers is smaller than that of the light-transmitting sheet; and a refractive index of the third light-transmitting layer is larger than those of the first and second light-transmitting layers. The third light-transmitting layer has a diffraction grating parallel to the light-transmitting sheet. At least a part of the photoelectric conversion section is located along an outer edge of at least one of the surfaces of the light-transmitting sheet.