A tractor includes booms, lift cylinders, a hitch, dump cylinders, a magnetic valve, a speed-up circuit, and a speed-up restricting arm. The lift cylinders swing the booms upward and downward by an operating oil being supplied thereto. The hitch is provided to the booms to allow an implement to be attached thereto. The dump cylinders swing the implement upward and downward by the operating oil being supplied thereto. The magnetic valve switches between supplying the operating oil to the dump cylinders and supplying the operating oil to a grab cylinder provided in the implement. The speed-up circuit is able to perform a speed-up operation for increasing the flow rate of the operating oil supplied to the magnetic valve. The speed-up restricting arm is arranged near the speed-up circuit. The speedup restricting arm is brought into contact with a contact member attached to an input member for switching an operation of the speed-up circuit, to thereby restrict the speed-up operation, so that a speed-up of the grab cylinder is prevented.