Ceramic electrolysis method that had been developed for tokamak exhaust processing can be applied for the process of highly tritiated water. Aiming to enhance the efficiency of ceramic electrolysis method, we developed new electrodes using cerium oxide (Ceria). We prepared electrodes by two manufacturing methods. One is to mix ceria into Pt paste and then electrode was sintering on the Yttria stabilized Zirconia (YSZ). The other is to use Ceria as intermediate layer between YSZ and Pt-YSZ electrode. In addition to this, different ceria concentrations of electrodes, 10%, 20% and 30%, were prepared for Ceria adding electrode. The water decomposition performance of such electrodes and usual electrode using Pt-YSZ was confirmed in different humidity at 1073K. Both electrodes using Ceria showed higher water decomposition performance than that of usual electrode. Especially, 30% ceria adding electrode showed highest performance and the decomposition efficiency was one order magnitude higher than that of usual electrode.