To provide a device for treating air for blasting into a blast furnace at high degree and its utilizing method with which high temperature oxygen having high utilizing value can be taken out from a part of the air for blasting into the blast furnace produced in a large volume without lowering the productivity (producing efficiency) in a hot stove for blast furnace and the blast furnace and also, deoxygenized air at the gas exhausting side can efficiently be utilized, as effective utilizing technique of the air for blasting into the blast furnace of a product producing in the hot stove for blast furnace.

The device for utilizing the air for blasting into the blast furnace in the hot stove for blast furnace is provided with the hot stove for blast furnace, an oxygen separator capable of separating oxygen from oxygen- containing high temperature gas, a hot air extraction line for introducing into the oxygen separator by extracting a part of the air for blasting into the blast furnace heated in the hot stove for blast furnace and a recycle line for mixing the deoxygenized air after separating the oxygen with the oxygen separator into the air for combustion in the hot stove or blast furnace.