The method for producing at least one notch in an outer wall of a tube includes guiding a first punch being made of a preforming tooth, causing the preforming tooth to penetrate through the wall of the tube until a protuberance is formed, positioning a solid cylindrical mandrel inside the tube. Then, the method includes guiding a second punch with a punching tooth, a leading end of the punching tooth having a shape complementary to a shape of the notch to be made in the wall of the tube, positioning a punching mandrel inside the tube, and having a groove suitable for containing the upset material. The invention can be used for notching headrests for the seats of a motor vehicle.