A solid-state imaging element or the like capable of limiting an abrupt refractive index distribution and collecting incident light at high efficiency is provided. The solid-state imaging element (size: 5.6 μm square) has a distributed index lens, a G color filter, Al wiring, a signal transmitting unit, a planarizing layer, a light receiving element (Si photodiode) and a Si substrate. A concentric structure of the distributed index lens is formed of SiO2 (n=1.43). This structure is a two-stage structure having film thicknesses of 1.2 and 0.8 μm. The distributed index lens is constructed by cutting concentric circular recesses into SiO2 and has a planar region about the center. A medium surrounding the lens is air (n=1).