An electronic control unit includes an input interface having multiplexer circuits, each of which circuits is supplied with input signals supplied from an outside of the electronic control unit, and a failsafe processing part that determines whether an abnormality occurs in the input interface by referring to a state of a specific multiplexer circuit that is at least one of the multiple multiplexer circuits when determining that an output signal of the input interface has an abnormal state and executes a failsafe process based on results of determination as to whether an abnormality occurs in the specific multiplexer circuit.