PURPOSE: To extend the service life of a fluorescent lamp by specifying the outer diameter of a bulb, sealing pressure for gases sealed therein and an electrode.

CONSTITUTION: Mercury and argon gas with sealing pressure between 266.6 and 400pa are sealed into a bulb 20 having a phosphor film formed on the internal surface and an outer diameter between 23 and 27mm. Also, bases 21 and 21 fitted to both ends of the bulb 20 are provided with connection pins 22 and 22. In addition, an electrode formed out of a tungsten-made triple coil having main winding diameter between 50 and 65μm, primary winding diameter between 95 and 120μm, secondary winding diameter between 200 and 250μm and tertiary winding diameter between 450 and 600μm, and an emitter with each tertiary winding gap between 500 and 700μm is laid between the pins 22 and 22, thereby forming a fluorescent lamp FL.