PURPOSE: To improve the brightness of a lamp due to an increase in a lamp current and remarkably lessen a glimmer during lighting by setting getter quantity to absorb impure gases to be a specified level or higher.

CONSTITUTION: Cold cathodes 3a, 3b installed on both ends of a bulb 2 whose inner circumference is coated with a phosphor coating 4 have V-shape tilting faces and a mercury alloy and getters 7a, 7b are deposited and fixed on respective inner and outer faces of the cathodes. A prescribed amount of mercury is emitted to the inside of the bulb 2 from the mercury alloy at the time of electricity application and the getters 7a, 7b made of an alloy consisting of zirconium and aluminum absorb the impure gases existing inside the bulb 2 to prevent snaking of a light column. By setting the total amount of respective getters per unit volume and unit lamp current inside the bulb 2 to be 0.04mg/ mA.cm3 or higher, glimmer during lighting can be remarkably decreased even if the lamp current is increased to improve the brightness of the lamp.