A semiconductor device includes a high-breakdown-voltage transistor having a semiconductor layer. The semiconductor layer has an element portion and a wiring portion. The element portion has a first wiring on a front side of the semiconductor layer and a backside electrode on a back side of the semiconductor layer. The element portion is configured as a vertical transistor that causes an electric current to flow in a thickness direction of the semiconductor layer between the first wiring and the backside electrode. The backside electrode is elongated to the wiring portion. The wiring portion has a second wiring on the front side of the semiconductor layer. The wiring portion and the backside electrode provide a pulling wire that allows the electric current to flow to the second wiring.