PURPOSE: To obtain a smooth inching operation by providing an economic switch for detecting the depression of an inching pedal and setting a current limiter to an operating state and a power OFF switch for interrupting the current to the motor.

CONSTITUTION: When an inching pedal 5 is depressed in the state that an accelerator pedal is depressed, and economic switch 16 is switched from closed state to open state, the driving force of a traction motor becomes small, and a vehicle moves at the slop speed. When the pedal 5 is further depressed, a power OFF switch 30 is opened, thereby interrupting the current to the motor and the brake unit is operated with the result that the vehicle is stopped. When the pedal 5 is returned, the brake unit is returned to non-operating state, the current is supplied to the motor, and the vehicle moves slowly. At this time the pedal 5 is maintained at the position for holding the switch 16 open. Thereafter, the pedal 5 is depressed to the position that the switch 30 is considered to be opened at the adequate time. When these operations are repeated, the inching movement can be performed.