A surge protective circuit and a noise filter circuit are provided in a power-supplying line, the surge protective circuit is adapted for protecting a switching device from surge voltage generated during operation of an electric motor and the noise filter circuit is adapted for absorbing noise generated during operation of the switching device, each of the surge protective circuit and the noise filter circuit include a plurality of elements, wherein at least one of the plurality of the elements constructing the surge protective circuit is used as at least one of the plurality of the elements constructing the noise filter circuit in common with each other.