To reduce the cost of the whole lens system of a radial type GRIN lens by filling at least one of surfaces transmitting light with a filler material without being polished.

The non-polished surface 2 of a radial type GRIN lens 1 is arranged adjacently to the image pickup surface 4 of an image pickup element 3 such as CCF, and a filler medium 5 such as resin or adhesive is filled between the non-polished surface 2 and the image pickup surface 4. The polishing of the surface is omitted, whereby the cost of a single body can be reduced. Further, this surface is filled with a filler medium such as resin or adhesive, so that the light is optically transmitted without scattering even when the surface is in the sanded state. Thus, the refractive index difference in the boundary surface is reduced even when the lens surface 2 of the radial type GRIN lens 1 is formed of a sanded surface, and the light can be passed as designed without being influenced by the irregular reflection by the surface or the waviness. The surface roughness of the sanded surface is desirably 0.5≤H$30.