The control apparatus-integrated generator-motor has: a generator-motor; and a control apparatus that is constituted by an inverter, a control circuit, a temperature sensor, etc. The control circuit determines whether or not switching element temperature will exceed the maximum permissible temperature when a command for an automatic engine stopping operation is issued. Then, if it is determined that the maximum permissible temperature will be exceeded, generated output of the generator-motor is reduced immediately before the automatic engine stopping operation in such a way that the switching element temperature will not exceed the maximum permissible temperature. The engine is subsequently stopped automatically.