Abstract: It is provided as shown in the drawing with a waste gas guiding duct, a rotating duct, an inserting duct, a connecting duct, a stationary duct, and a branch tube including a feed chute and a gas exhaust duct, and is adapted to preheat a main raw material consisting of direct reduced iron or small lumps of pig iron, or of auxiliary raw materials consisting of ferro-alloy and quick lime by utilizing the waste heat of a waste gas generated in a steel making furnace, weighing the total raw materials, and charging these raw materials into the electric furnace. This enables the energy to be utilized efficiently, and the quality and productivity to be improved.