A stator 60 is rotated in a direction opposite to that of a rotor 20 to improve output of a generator 9. A stator 60 is rotationally fixed to a main shaft 10. A rotor is fixed to the main shaft rotated by outer force. A main gear 25 is fixed to the main shaft. A ring gear 32 is fixedly positioned with respect to the stator. Pinion gears 43 are disposed between the mains shaft and the ring gear. Rotation of the main shaft in a forward direction rotates the stator in a reverse direction. A pair of slip collars 4a, 4b are concentrically mounted to the rear cover 71 that concurrently rotates with the stator. Output circuits 6a, 6b, 6c of the stator coils 5a, 5b, 5c are connected to the slip collars. Brushes 7a, 7b for slip collars are connected to a rear-side base member 55 fixedly secured to a base plate 50. Electricity is output through the brushes for slip collars.