Abstract Hyuga Smelting Co., established by Sumitomo Metal Mining Co., started the production of ferro-nickel by the sintering-electric furnace process in September 1956. In accordance with the rapid increase in market demands, the company made a steady growth, expanding the production capacity from 30 to 200 tons of nickel per month. Because further expansion required greater productivity and more space, a new plant was built at the present site in the coastal industrial quarter in 1968 adopting the rotary kiln-electric furnace process. Since the improvement to the process, and with the development of new products and the energy curtailment, of the whole plant, Hyuga Smelter has become one of the most advanced coastal ferro-nickel smelters, having the most modern facilities and most advanced technical knowledge. The production capacity is 2,200 tons of nickel per month. This paper briefly reviews the developments in technical knowledge and cost saving: (1) improvement of the ore sizing; (2) substitution of heavy oil and anthracite by bituminous coal; (3) adopting the pelletizing for the treatment of the rotary kiln dust; and (4) energy savings of the electric furnace and its apparatus.