A lead frame comprises on a same plane, a pad part including an LED chip mounting upper surface A on which at least an LED chip is to be mounted, and a lead part including an electric connection area C in which an electric connection with the LED chip is made. A relationship between an area S1 of the mounting upper surface of the pad part 2 and an area S2 of a radiating lower surface opposite to the mounting upper surface is represented by 0S1S2. Side surfaces of the pad part between the mounting upper surface and the radiating lower surface are provided with stepped parts or tapered parts which spread in a direction from the mounting upper surface toward the radiating lower surface and hold a resin-filled during molding.
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