A semiconductor device includes a first wiring; a first circuit region provided with a first power supply wiring and a first ground wiring; a second circuit region provided with a second power supply wiring and a second ground wiring; and a bidirectional diode connected between the first and second ground wirings, and provided with first and second diodes. The first diode includes a first impurity region of a first conductive type, connected to the second ground wiring, and a second impurity region of a second conductive type, connected to the first ground wiring. The second diode includes a third impurity region of the second conductive type connected to the second ground wiring, and a fourth impurity region of the first conductive type connected to the first ground wiring. Any of the first to fourth impurity regions, or any combination of the impurity regions is connected to the first wiring.