Effects of mixed conducting oxide added for Ni-Fe were studied as fuel electrode of Solid Oxide Reversible Cells (SORC). For SOFC operation, power density is larger as the following order, Ce(Mn,Fe)O2<NiFe=La(Sr)Ga(Mg)O3<Ce0.8Sm0.2O2<La(Sr)Fe (Mn)O3. On the other hand, for electrolysis operation, the electrolysis current density is increased in the following order, Ce(Mn,Fe)O2<<NiFe<La(Sr)Ga(Mg)O3<< La(Sr)Fe(Mn)O3 <Ce0.8 Sm0.2O2. Therefore, for reversible operation, NiFe-Ce0.8Sm0.2O2 (SDC) seems to be the most active. Degradation of the cell using NiFe-SDC and Sm0.5Sr0.5CoO3 for fuel and air electrode, respectively, was studied at 1073 K, 100mA/cm2. The observed terminal potential was 1.13 and 1.025 V for SOEC and SOFC respectively at initial cycle and the observed potential slightly increased for SOFC and decreased for SOEC with increasing cycle number, however, after 50 cycles; the observed terminal potential was 1.15 and 1.0 V for SOFC and SOFC, respectively. Therefore, the degradation is hardly observed for the reversible operation of the cell. Combination of SORC with metal oxidation could open a new application area for fuel cell. In this study, application of SORC for reversible metal-air battery has been studied.