PURPOSE: To eliminate a generation of sander phenomenon, by means of applying to construct a phosphor film so that a conductive film may be disclosed to more than specific proportion from the phosphor film.

CONSTITUTION: Onto a conductive film formed on inner surfaces of the tube, is constructed a layer of phosphor film. At this time, the phosphor film is so applied and constructed that the conductive film may be exposed more than 3% above from the phosphor film. With the proportion of exposure of the conductive film exceeding 15%, a total light flux is lowered. In is preferable for the range to be from 3 to 10%.