Cathode ray tube

An image display device includes a cathode ray tube. The cathode ray tube includes a panel with an inner phosphor screen, and a funnel connected to the panel with a cone portion mounting a deflection unit on the outer circumference thereof. A neck is connected to the funnel while mounting an electron gun therein. The interface between the cone portion and the neck is called a neck seal line, and the portion of the electron gun sealed to the neck called a gun sealing portion. When the distance between the panel and the neck seal line is indicated by A and the distance between the neck seal line and the gun sealing portion by B, the values of A and B satisfy the following conditions: 0.31 < B / A < 0.38 and 79 mm < B < 95 mm .