A support rod for a vehicle seat head restraint, which is formed as a tube, having at least one structure as part of a locking device and intended for cooperating with a catch of the locking device which is associated with a holding structure. The structure has a base surface which prevents movement of the catch radially to a central axis of the support rod and includes a catch surface that prevents, together with the catch, movement of the support rod in a first direction. At least one catch structure as a detent structure has a cut-out tongue. An inner surface of the tongue radially facing a central axis of the support rod at a free end being spaced apart from the base surface by a height so that the catch is movable at least with a partial region radially under a region of the inner surface of the tongue.