To avoid melting, vacuum leakage, and a shortage of a discharge substance of a glass tube caused by heating of the discharge substance or a mercury getter of a cold cathode discharge tube.

This manufacturing method prepares a glass tube assembly 1 having the glass tube 2 for forming an inside cavity 3 held in a low pressure state, a pair of electrodes 4 fixed to both ends of the glass tube 2, a light emitting layer 5 arranged on an inside surface 9 for forming the inside cavity 3 of the glass tube 2, and a metallic vessel 6 arranged in the inside cavity 3 of the glass tube 2, and housing the discharge substance 7. The metallic vessel 6 is heated by a high frequency induction heater 8 arranged outside the glass tube 2, and because of cooling an outside surface 10 of the glass tube 2 adjacent to the metallic vessel 6 while vaporizing the discharge substance 7 in the inside cavity 3, a crack or damage caused in the glass tube 2 is prevented, and consumption of the discharge substance 7 by the heating can be prevented.