A lead frame to be used for a semiconductor device, comprising: a heat sink having a peripheral area and a central projected land on which a semiconductor chip is to be mounted. The heat sink has a relatively good heat radiating characteristic. A plurality of inner leads are provided, each having an inner end superimposed on the peripheral area of the heat sink by an insulating material. A semiconductor chip has a chip surface on which a junction pattern is arranged, and is mounted on the projected land of the heat sink by an insulating adhesive so that the chip surface faces the projected land. TAB leads are provided for electrically connecting the semiconductor chip to the inner leads, and a sealing resin hermetically seals at least the semiconductor chip.