PURPOSE: To enhance the efficiency of loading operations by automatically varying and extending reach of a lift arm by a method in which a slider is provided at the tip of a lift arm, a link mechanism is provided to the slider, and the slider is moved back and forth by vertically moving the lift arm.

CONSTITUTION: A slider 4 is provided in the longitudinal direction of a lift arm 2 at the tip of the lift arm 2 whose basal end is pivotally supported on a vehicle in a vertically rocking manner. A bucket 5 is pivotally supported on the tip of the slider 4 in a vertically rocking manner, and the lift arm 2 is attached with a lift cylinder 3 in a vertically rocking manner. The center of the 5th link 6-6 is pivotally supported on the basal end of the slider 4, its one end and the bucket 5 are connected with the bucket cylinder 7, and the other end and the lift arm 2 are connected with the 4th link 6-4. The first, second, and third links 6-1, 6-2, and 6-3 are connected to the lift arm 2, the slider 4, and the vehicle 1. The reach of the lift arm can thus be extended.