Abstract: A glow discharge tube for exciting a sample in emission spectrochemical analysis or mass spectrometry, in which glow discharge is effected between the anode tube and the sample while gas is being passed, for exhaust, through the narrow gap formed between the sample surface and the end of the insulating tube fit on the anode tube so as to maintain a constant pressure in the anode tube. Since the insulating tube projects further than the anode tube toward the sample side, a shortcircuit is never formed between the anode and the cathode even if sample vapor adheres to the walls surrounding the exhaust passage. As a result, efficient analysis can be achieved with the glow discharge tube of the present invention.