To provide a fluorescent lamp which has a high tube wall load and a long life.

This fluorescent lamp characterized in that the composition of the glass bulb 3 of a luminous tube 1 in which mercury is sealed comprises SiO2 65 to 75 wt.%, Al2O3 0.5 to 4 wt.%, B2O3 0 to 3 wt.%, Li2O 0 to 2 wt.%, Na2O 1 to 7 wt.%, K2O 1 to 8 wt.%, MgO 0.5 to 5 wt.%, CaO 1 to 8 wt.%, SrO 1 to 7 wt.%, BaO 4 to 6.5 wt.%, Sb2O3 0 to 1 wt.%, CeO2 0 to 1% wt.%, and TiO2 0 to 1 wt.%. The tube wall load of the luminous tube is in the range of 0.10 to 0. 20 W/cm2.