In a non-insulated DC-DC converter having a circuit in which a power MOS.cndot.FET high-side switch and a power MOS.cndot.FET low-side switch are connected in series, the power MOS.cndot.FET low-side switch and a Schottky barrier diode to be connected in parallel with the power MOS.cndot.FET low-side switch are formed within one semiconductor chip. The formation region SDR of the Schottky barrier diode is disposed in the center in the shorter direction of the semiconductor chip, and on both sides thereof, the formation regions of the power MOS.cndot.FET low-side switch are disposed. From the gate finger in the vicinity of both long sides on the main surface of the semiconductor chip toward the formation region SDR of the Schottky barrier diode, a plurality of gate fingers are disposed so as to interpose the formation region SDR between them.