The invention provides a curable resin composition which comprising: 100 parts by mass of a main component (X) (a refractive index: RIX) containing at least one of a silicone resin, a modified silicone resin, an epoxy resin and a modified epoxy resin, and exceeding 0 part by mass and 100 parts by mass or less of an additive (Y) (a refractive index: RIY) containing at least one of a silicone resin, a modified silicone resin, an epoxy resin and a modified epoxy resin, and having a different refractive index as that of the main component (X) being added and dispersed therein, wherein the difference of the refractive indexes of the main component (X) and the additive (Y) being |RIX−RIY|≧0.0050 in an uncured state.