Abstract: An auxiliary machine driven by an engine comprises: an operating section operated by a rotary motion and having a drive shaft; an input shaft, one side of which is connected to the engine and the other side of which is connected to the operating section; a clutch for connecting the engine to the input shaft and for disconnecting the engine from the input shaft; an electric motor; a planetary gear mechanism arranged between the input shaft and the output shaft; a first rotary direction regulating means for inhibiting a rotary direction of the input shaft in one-direction; and a second rotary direction regulating means for inhibiting a rotary direction of the drive shaft.