To make synthetic resin material sufficiently contribute to reduction of ore and to reduce the fuel ratio by mixing and forming a specified ratio of the synthetic resin material and the fine ore and charging this formed body from the furnace top of a blast furnace.

In the blast furnace operation, the formed body mixing and forming the powdery ore and if necessary, the other raw material to the synthetic resin material so that the content of the synthetic resin material becomes 10-90 wt.%, is charged from the furnace top of the blast furnace. The heat transfer is delayed to the waste synthetic resin material by mixing the waste synthetic resin material with the powdery ore and forming a briquette, and thermal decomposition and gasifying reaction are shifted to high temp. side and the generated gas is contributed to the reduction of the gas and the reduction ratio is improved. The formation of the mixture of the synthetic resin material and the powdery ore is used for a compression-formation, such as roll-formation, die-formation, extrusion-formation. For example, the synthetic resin material constituted with 60% polyethylene and 40% polyethine, is thermal- decomposed and gasified at a temp. of 450-550°C.