a smelting reduction apparatus which separates exhaust gas , which is exhausted from a melter - gasifier or a fluidized bed reactor , into dusts and reducing gas to supply them to each fluidized bed reactor respectively is disclosed , in which the smelting reduction apparatus includes a three - stage type fluidized bed reactor , a melter - gasifier for manufacturing molten pig iron by finally reducing the fine iron ores of which reaction is finished in a final fluidized bed reactor , and a dust separating device , which performs separation of exhausted gas from the melter - gasifier into dusts and reducing gas , so as to supply the separated reducing gas to a lower part of the final fluidized bed reactor , dusts having a larger particle sizes in the separated dusts to the melter - gasifier again , and fine dusts having a smaller particle sizes in the separated dusts to an upper part of a gas distributor of the final fluidized bed reactor .