According to one embodiment, a semiconductor device includes an interface, a power supply, a driver, and a switch section. The interface includes a first MOSFET and converts a terminal switch signal of input serial data into parallel data. The first MOSFET is provided on the SOI substrate and has a back gate in a floating state. The power supply includes a second MOSFET and generates an ON potential higher than a potential of a power supply to be supplied to the interface. The second MOSFET is provided on the SOI substrate and has a back gate connected to a source. The driver includes a third MOSFET and outputs a control signal for controlling the ON potential to be in a high level according to the parallel data. The third MOSFET is provided on the SOI substrate and has a back gate connected to a source.