A device for lightening the weight of vehicle components includes a tooling provided with a seat wherein the component is formed and a plurality of moveable bodies, which are moveable between an initial position and a final position, such that in the final position one end of each moveable body penetrates the seat of the tooling to form a cavity to lighten the weight of a component of the vehicle, wherein at least one of the moveable bodies can move laterally. Such device allows lightening the weight in a more simple and productive way than in currently known systems. This is achieved because the moveable bodies do not interfere with each other during the movement thereof, such that the lightening process can be done in a single blow during a forging procedure.