To provide an ultraviolet discharge lamp increased in illuminance of a specific wavelength by applying a phosphor for ultraviolet luminescence having luminescence in a short wavelength region.

Soda-lime glass providing transmittance not smaller than 80% at a wavelength of 320-340 nm required for this ultraviolet discharge lamp is used for a transparent glass arc tube 11 made of soda-lime glass containing sodium oxide not smaller than 10% in 100% of a base material. For instance, the tube diameter D and tube length L of the arc tube 11 are 38 mm and 2,650 mm, respectively, and the arc tube 11 is filled with a rare gas such as argon gas, and a certain quantity of mercury. An ultraviolet emission type phosphor having a peak of conversion efficiency in 300-340 nm is applied to the inside surface of the arc tube 11. Thereby illuminance in 320-340 nm can be improved.