PURPOSE: To prevent oxidation of a mercury-discharging compound and the discharge of any of this material out of a discharge tube during the manufacturing process of the tube, by coating with a boric system compound the mercury-discharging compound included in a mercury-discharging structure which supplys mercury into the tube.

CONSTITUTION: A mixture powder 2 consists of a getter-member powder made of a zirconium-nickel alloy, and a metal compound powder which consists of metals having face-centered cubic lattices and mainly contains yttrium, nickel and mercury. The powder 2 is packed into a case 1, before it is immersed in an alcohol solution containing boric anhydride and is heated at 450W550°C in vacuum to make the mixture-powder body 2 coated with a boric-system-compound film 3, and thus a mercury-discharging structure 4 is made. Consequently, when the body 4 is fixed within a fluorescent lamp 6, both the oxidation of the body 4 and the discharge of any mercury out of a discharge tube can be prevented even during the manufacturing process of the tube, and a given amount of mercury can be always sealed in the tube.