PURPOSE: To turn a moving body into an optional direction, by making driving units of moving wheels and supporting the driving units at a prescribed inclination as to the moving body and by tilting the driving units into a prescribed direction to change the direction of movement of the moving body.

CONSTITUTION: A driving unit A comprises a moving wheel 1 pinch-held between a wheel suporting ring 2 and a wheel securing plate 3, and an electric motor 5, to which the ring is coupled through a speed reducer 6. A pair of such driving units A are pivotally connected at a prescribed angle to both the ends of a support frame 8 fitted on the mounting frame of a moving body by pins 10. A tilting electric motor is driven to change the direction of inclination of the driving units A through a worm wheel 16, a wheel 16, a joint 12 and links 11, 13, 14. Switches for operating the motors are provided on a switch mounting plate 21 rotatably fitted on a worm wheel shaft 20.