An apparatus for manufacturing molten iron includes i) at least one fluidized-bed reduction reactor that converts iron ore into reduced materials by reducing and plasticizing the iron ore, ii) a melter-gasifier into which the reduced materials are charged and oxygen is injected such that the melter-gasifier manufactures molten iron, and iii) a reducing gas supply line that supplies a reducing gas discharged from the melter-gasifier into the fluidized-bed reduction reactor. The fluidized-bed reduction reactor includes a gas injector that injects a gas into the fluidized-bed reduction reactor to remove stagnating layers.