A smelting reduction apparatus and a method for producing molten pig iron using the smelting reduction apparatus are disclosed. The molten pig iron is produced by using iron ore, sintered ore or iron pellets, so that the reduced iron discharge operation from a pre-reducing furnace to a melter-gasifier would not give any influence to the operation of the pre-reducing furnace. An iron ore is pre-reduced at a pre-reducing furnace by utilizing a reducing off-gas which is produced from a melter-gasifier. The pre-reduced iron ore is melted and reduced at the melter-gasifier. The reducing gas which is discharged from the melter-gasifier is supplied through an ascending duct and a cyclone into the pre-reducing furnace. The fine iron ore which is collected at the cyclone is spouted through a recycling device and a melter-burner into the melter-gasifier. A part of the reducing off-gas which has passed through the cyclone is supplied through a ventury scrubber, a compressor and a compressed gas circulating duct into the ascending duct. In such an apparatus, a reduced iron discharge device is installed between the pre-reducing furnace and the melter-gasifier.