A method of producing reducing gases from oxide ores, particularly iron ores, which contain mainly carbon monoxide and hydrogen and which are employed in the reduction process with a two to three fold excess with regard to the stoichiometric requirement of the ore to be reduced, comprising, mixing a hot moist fresh reducing gas and a preheated recycled gas, both of which are used in reducing iron ores and mainly contain carbon monoxide and hydrogen, directing the mixed gases in counterflow heat exchange with iron sponge in a desulfurizer to treat the sponge, thereafter, directing the treated sponge into an oxidizer and circulating preheated air thereover to lightly oxidize the iron sponge, and subsequently, directing the lightly oxidized iron sponge into a reducing shaft along with the mixed gases which are taken out of the desulfurizer.