To prevent the clustering in a preliminary reduction furnace, to improve the preliminary reduction efficiency in said furnace and to decrease the rate of supply of a carbon material, etc. to a melt reduction furnace by coating a C-component on the surface of the iron ore, executing the preliminary reduction and supplying the generated gas to the preliminary reduction furnace. Iron ore Or and hydrocarbon are introduced into a carbon- component coating device 3 and the iron ore coated with the carbon-component is supplied to the preliminary reduction furnace 1. On the other hand, a cracked gas G2 which is the waste gas from the device 3 is joined with the generated gas G1 flowing from the melt reduction furnace 2 toward the above-mentioned furnace 1 to execute the cracking reaction and to improve the reducing characteristic. The gas is introduced into the furnace 1 to accelerate the melt reduction after the temp. thereof is decreased down to the temp. at which welding does not arise. |