To provide a fluorescent lamp having an excellent luminous flux maintenance factor unavailable in the past.

A protective layer 8 made of inorganic powder is formed between the inner face of the translucent airtight container 1 of this fluorescent lamp and a phosphor film 3. This inorganic powder has the volumetric percentage below 42.5% against the apparent volume of a compact obtained by compression molding at the pressure of 3000 kgf/cm2. When the glass protective layer 8 is made of the inorganic powder satisfying this condition, the barrier function minimizing various damages that the inorganic powder of the glass protective layer 8 causes luminous flux deterioration is exerted, and the preventing effect of luminous flux deterioration can be improved as compared with that in the past.