PURPOSE: To prevent crack initiation in an anode base board when in the process it is sealed, by interposing a dummy spacer between the anode base board and cover glass of the surface facing a surface where a lead is led out.

CONSTITUTION: In a fluorescent character display tube of such a structure that a grid is placed directly on an anode base board 1, a frame having a dummy spacer 4 between spacers 3 at the ends is pinched between cover glass 2 and the anode base board 1, and the cover glass 2 and anode base board 1 are sealed fast by applying pressures from above and below. Then the frame is cut at the sealing part. The deformation amount of the anode base board 1 when it is sealed. is decreased by providing in this manner a plurality of dummy spacers between the spacers 3, and crack initiation is prevented.