To materialize a discharge tube excellent in surge response and repetitive discharge characteristics.

In the discharge tube 10, emitter layers 14, 14 are adherently formed on the surfaces of a pair of electrode substrates 12, 12 to make discharge electrodes 16, 16, lead terminals 18, 18 are connected to the lower end parts of the respective electrode substrates 12, 12, a discharge gap 20 is formed by disposing both discharge electrodes 16, 16 side by side with a prescribed distance parted from each other, they are filled in an airtight vessel 22 together with a discharge gas, and the lead terminals 18, 18 of the respective discharge electrodes 16, 16 are derived by passing them through the lower end sealing part 22a of the air tight vessel 22. The emitter layer 14 is formed by making it contain quaternary oxide such as barium oxide, strontium oxide, calcium oxide, and magnesium oxide.