PURPOSE: To enhance the convergence of an electron beam and brightness of image by forming a superconductive film on the substrate of a shadow mask.

CONSTITUTION: A superconductive film 4 consisting of oxide type superconductor, etc., on the substrate 2 of a shadow mask. When an electron beam reaches the shadow mask 1, the magnetic field of electron beam 6 shrinks toward the center of an electron beam aperture 3 by Meissner effect of film 4 and is induced into the aperture 3. This enhances the convergence of the beam 6 to enable light emission in high grightness from a fluorescent plate 5. Therein the shadow mask will not run temperature, the doming phenomenon is prevented, and no chromatic misconvergenge is generated.