To reduce the environmental pollution due to exhaust gas and improve the performance at the high sped traveling by providing a storage battery in a traveling body, driving a hydraulic unit by the storage battery to generate hydraulic pressure, driving a mechanical output device by hydraulic pressure, and providing a change gear device which changes transmission rotation speed at muti-stage and transmits to a power take-out shaft.

A traveling body is provided with a storage battery 3 and a hydraulic unit 2 which is driven by the storage battery and generates hydraulic pressure. In the hydraulic unit, mechanical output devices 5 are mutually connected by pipes 11a and 11b. A hydraulic motor is driven buy the storage battery, hydraulic oil from a hydraulic tank is discharged by a hydraulic pump 9 by the opeartion of a control valve to supply it to hydraulic cylinders 10a, 10b, and return oil is returned into the hydraulic tank. Speed change gears 7a, 7b of a transmission 7 are provided between an input shaft and an output shaft 4, a shifter 18 is moved, a position of the speed change gear 7a is changed, and meshing with the speed change gear 7b is selected to change speed among high, middle and low speeds. The number of rotation from the output shaft 4 is changed to change running speed of an automobile.