Abstract: A good discharge lamp which can emit light with wavelengths in the range of 220 nm in an amount sufficient for industrial applications and at the same time can adequately maintain a transmission factor of the radiant light and emits neither water nor hydrogen or the like during luminous operation is achieved by the fact that, in a discharge lamp in which a pair of electrodes are located adjacent to one another encapsulated within a quartz glass fluorescent tube together with mercury and an inert gas, the quartz glass contains an OH radical concentration of a weight of in the range of 300 to 800 ppm. Furthermore, the content of metallic impurities in the quartz glass is limited to a weight less than or equal to 1 ppm.