
A discharge tube of the present invention is disclosed comprising an electrically insulated container which is further provided with a pair of electrodes at opposite sides thereof and with inert gas and mercury enclosed therein, wherein the enclosed quantity of the mercury is 0.01 to 1 mg per one cubic centimeter of the capacity of the container and the enclosing pressure of the inert gas is 8 to 15 kgf/cm.sup.2.











