A semiconductor device according to an embodiment includes a normally-off transistor having a first drain, a first source electrically connected to a source terminal, and a first gate electrically connected to a gate terminal, a normally-on transistor having a second gate, a second source electrically connected to the first drain, and a second drain electrically connected to a voltage terminal, a first capacitor provided between the gate terminal and the second gate, a first diode having a first anode electrically connected to the first capacitor and the second gate, and a first cathode electrically connected to the first source, a coil component provided between the voltage terminal and the second drain, and a second diode having a second anode electrically connected to the first drain and the second source, and a second cathode electrically connected to the coil component and the voltage terminal.