A panel is provided with a substantially rectangular effective portion that has a substantially flat outer surface, and a phosphor screen is formed on the inner surface of the effective portion. A shadow mask that is opposed to the phosphor screen includes a substantially rectangular mask body formed having a large number of electron beam holes and a mask frame supporting the peripheral edge portion of the mask body. The interval between the electron beam holes in the direction of the major axis of the mask body increases from the center of the mask body toward the major axis end so that the rate of change of the interval has a maximum value in the region between the center of the mask body and the major axis end.