There is provided a cathode which is easily operable, harmless, and stable at high temperature at least 1,400° C. as well as excellent in electron emission characteristics at the same time, and the process for preparing the same. The cathode of the present invention comprises a polycrystalline substance or a polycrystalline porous substance of high-melting point metal material and an emitter material dispersed into said polycrystalline substance or polycrystalline porous substance in an amount of 0.1 to 30% by weight in the cathode, wherein the emitter material comprises at least one selected from the group consisting of hafnium oxide, zirconium oxide, lanthanum oxide, cerium oxide and titanium oxide.