To provide a semiconductor device where electrostatic discharge breakdown resistance of an NMOS transistor, in which a pull-down resistor is provided between a gate and a source, is improved in the NMOS transistor of an open drain where a drain is connected to an external terminal.

An NPN transistor, where an emitter is connected to a drain and a base, a collector are connected to a GND, is provided between the drain and the GND of a NMOS transistor of the open drain.