A projection picture tube includes a bulb, a sealing chamber disposed in contact with a front surface of a phosphor screen panel of the bulb and sealed with a liquid coolant, and a holding mechanism for holding the sealing chamber by the bulb. The sealing chamber includes a transparent member disposed in front of the phosphor screen panel to be spaced apart therefrom, a heat dissipation member which is disposed between the transparent member and the phosphor screen panel and part of which is in contact with the liquid coolant sealed in the sealing chamber, seal members respectively disposed between the heat dissipation member and the phosphor screen panel and between the heat dissipation member and the transparent member, and a holding piece for holding the transparent member on the heat dissipation member. The holding mechanism is coupled to the heat dissipation member.