The light source unit is provided with a substrate and a decorative cover having thermal conductivity. The substrate includes a circuit pattern area, in which a plurality of LED chips are disposed, at the middle part thereof, has thermal conductivity, and transmits heat from the circuit pattern area to an area in the outer circumferential direction thereof. The decorative cover encloses the substrate, is electrically insulated from the circuit pattern area, and is thermally coupled to the surface side of the substrate at the periphery of the circuit pattern area by being face-contacted thereto. Heat of the substrate can be radiated by the decorative cover while securing an electric insulation property with respect to the circuit pattern area.