PURPOSE: To prevent breakdown by crack by providing a glass breakdown preventing tape in the initial stage of manufacturing the cathode ray tube and by winding a protection tape when providing the explosion proof mechanism.

CONSTITUTION: A glass breakdown preventing tape 21 is provided to a side wall part 11 of the outer casing. As a tape 21, a metal material, for example, teflon, polyimide, copper foil, glass cloth, etc. in the heat proof insulating class of E, B, F, H and C is effective and a silicon system bonding agent is effective. After completion of sealing of electron gun, heating and exhaustion processes, a protection tape 22 for preventing glass heat shock and glass breakdown is wound. Next, an explosion proof mechanism 25 consisting of a tension band 24 having supporting metals 23 at the corners is provided on the protection tape 22 by shrinkage fitting.