A cathode ray tube having a phosphor layer formed on an inner surface of a panel of an envelope, a color selecting aperture grill formed of a number of grid elements and located within the envelope opposing to the phosphor layer, a metal wire for coupling the number of the grid elements, an electron gun located within the envelope and a deflecting device located around the envelope is disclosed, in which the resonance frequency of at least one grid element of the color selecting grid is selected different from that of another grid element in the vicinity thereof.