Due to a slit formed in the dead space, a cathode ray tube capable of preventing incorrect hitting of color electron beams caused by the local doming phenomenon from occurring and thus preventing displacement of colors, unevenness in colors, and deterioration of luminance from occurring is provided. The cathode ray tube comprises a shadow mask having an effective area where lines of apertures for passing electron beams are arranged and a dead space formed on both outer sides of the effective area. In the dead space, a slit extending along the lines of the apertures is formed. Accordingly, the thermal expansion of the dead space caused by a temperature increase can be reduced, and the stress applied to the aperture line of the effective area adjacent to the dead space can be suppressed. As a result, the local doming phenomenon can be prevented from occurring.