The invention describes a light burner (1) comprising a discharge chamber (2) containing a gas sealed in the discharge chamber (2) by a seal (4, 5) and a pair of electrode shafts (6, 7), each of which partially intrudes from the seal (4, 5) into the discharge chamber (2) whereby a wrapping (8, 9), at least partially contained in the seal (4, 5), is freely wound around at least one of the electrode shafts (6, 7) and constrained in its motion by a number of containment elements (P.sub.1, P.sub.2, P.sub.3, P.sub.4) positioned along the longitudinal axis of the electrode shaft (6, 7).