A semiconductor device includes: a semiconductor chip mounting substrate, a control circuit board, a power terminal holder and a semi-fixing member. The semiconductor chip mounting substrate includes a substrate, a semiconductor chip provided on a first major surface of the substrate, and a first and second semiconductor chip connection electrodes. The control circuit board is provided generally in parallel to the first major surface and includes a control circuit, a control signal terminal connected to the control circuit, and a through hole extending in a direction generally perpendicular to the first major surface. The power terminal holder is provided on opposite side of the control circuit board from the semiconductor chip mounting substrate and includes a power terminal. The semi-fixing member includes a shank portion and an end portion. The shank portion is fixed to the power terminal holder and penetrates through the through hole. A cross section of the shank portion in a plane orthogonal to the extending direction of the through hole is smaller than a size of the through hole. The end portion is connected to a tip of the shank portion. A cross section of the end portion in the plane is larger than the size of the through hole. The first semiconductor chip connection electrode is connected to a first terminal of the semiconductor chip and the control signal terminal. The second semiconductor chip connection electrode is connected to a second terminal of the semiconductor chip and the power terminal.