A bench-scale laboratory cell of 100 A was tested using cryolite-alumina electrolyte at 960℃ in a graphite crucible. The cell was built with a graphite cathode of 120 mm×40 mm×20 mm and a Fe - Ni - Co -Al₂O₃ cermet inert anode of 120 mm×80 mm×15 mm. The purity of aluminum metal produced was 98%〜99%, the impurities were mainly Fe, Ni and Co. The anode gas consisted of 98%〜99% O₂ which was analyzed with an Orsat apparatus. The back EMF value of the cell was 2.45 V at 960℃ , which was 0.25 V higher than the theoretical alumina decomposition potential 2.2 V. After 10 hour's electrolysis, the anode was only little corroded. Hence it was confirmed that the electrochemical reaction occurred in the electrolysis cell was the decomposition of Al₂O₃ in the bath and the anode used was inert.