To improve reliability of a semiconductor deviceA power MOSFET for switching and a sense MOSFET having an area smaller than that of the power MOSFET and configured to detect an electric current flowing through the power MOSFET are formed within one semiconductor chip CPH and the semiconductor chip CPH is mounted over a chip mounting part via an electrically conductive joining material and sealed with a resin. In a main surface of the semiconductor chip CPH, a sense MOSFET region in which the sense MOSFET is formed is located more internally than a source pad PDHS4 of the sense MOSFET region RG2. Furthermore, in the main surface of the semiconductor chip, the sense MOSFET region RG2 is surrounded by a region in which the power MOSFET is formed.