Abstract: A tubing coupling device constructed in accordance with this invention is comprised of a rigid body having cavity therein, an aperture communicating with the smaller end of said cavity and a tapered ferrule having an axial passageway that is aligned with the aperture. Means such as a nut that is in threaded engagement with the end of the rigid body opposite the aperture forces the ferrule into the cavity. The relative shapes and dimensions of the cavity and the ferrule are such that as the ferrule is forced into the cavity it is subjected to radial compression so as to attain intimate contact with the exterior surfaces of the end portions of tubes that are inside the ferrule.