PURPOSE: To simply form a depression section on a phosphor layer and prevent pits from occurring by applying a thickener in the suspension of the phosphor which is coated on the inside of a fluorescent tube for the main solvent at a specific mixing ratio.

CONSTITUTION: The mixing ratio of the thickener such as nitrocellulose to the main solvent of the suspension of the phosphor 2 is 2 weight percentage or more. By coating this suspension inside the fluorescent tube 1 on which the Nesa film 4 is formed using the pendency coating method and sintering it, a rapid start type fluorescent lamp is created. For example, the phosphor powder of 1kg is added to butyl acetate of 1 in which nitrocellulose is mixed by 3 weight percentage and the suspension is created. This is coated on the glass tube 1 of the fluorescent lamp in a fixed direction, dried, and sintered. As compared with the conventional method in which nitrocellulose is less than 1 weight percentage, this permits the porosity of the phosphor layer 2 to be improved and prevents pits from occurring after the lamp is used for a long time.