An emitter material for a CRT comprises mixed crystal or solid solution of at least two kinds of alkaline earth metal carbonate, wherein at least one alkaline earth metal carbonate is dispersed or separated in the mixed crystal or solid solution. The alkaline earth metal carbonate, which is an emitter material for the CRT, is coated onto the base metal and thermally decomposed in a vacuum to from an emitter of an alkaline earth metal. This emitter, which is proper for a larger screen size, high brightness and high resolution CRT, can be provided with enough life characteristics even under the operating condition of the emission current density of 2A/cm2.