To improve applications in accordance with purposes and selected articles to be transported by supporting a double arm lever on a shaft driven by an electric motor, providing the double arm lever with wheel holding bodies for supporting a wheel which can be restrained by a brake unit at end parts of both arms, and constantly holding the wheel holding bodies at the same relative angle positions by a connecting device.

A drive motor 17 is connected to a beam 15 formed on a double wall of a chassis, and it is rotated through an endless drive chain 18. A drive shaft 16 is shaft-supported by a bearing 33 on the beam 15, a double arm lever 20 is provided at an outer end part of the beam 15, and arms of it are rotated with the drive shaft 16. At an end part of each lever arm, a wheel holding body 34a, 34b for holding a wheel 21a, 21b through a bearing 35 is rotatably supported, and a brake curvature piece 38 of a restraining device is supported by a flange 36, 37 of it to be capable of oscillation. A connecting device for maintaining the restraining devices of the wheels 21a, 21b in the same direction comprises a chain transmitting device having an endless transmitting chain 41 provided in the double arm lever 20.