A semiconductor device includes a gate terminal, a ground terminal, a power-supply terminal, and a source terminal. The semiconductor device includes a first switch element having a gate and a source, the first switch element connected between the gate terminal and the source terminal, a second switch element connected between one of the gate of the first switch element and the source terminal or between the gate of the first switch element and the ground terminal and configured to switch the first switch element between turned-on and turned-off states, and a capacitor having one terminal thereof connected to the power-supply terminal and the ground terminal and another terminal thereof connected to the gate of the first switch element. Based on the potential state of the ground terminal and the state of the second switch element, the capacitor boosts the voltage of the gate of the first switch element.