PURPOSE: To reduce the cost owing to unnecessity of consumable lance pipe, to greatly reduce labor of a worker, to release the worker from dangerous work at the front of a furnace, to improve the productivity and to reduce the cost owing to the reduction of the consumption of carbon powder by half.

CONSTITUTION: In a blowing device 6 for blowing oxygen and the carbon powder into an electric furnace 1 for steelmaking through water-cooled non- consumable lances 13, 14 at the same time, an arm supporting stand 10 is arranged at the side part in the front of the electric furnace 1 and a lance holding arm 12 is arranged on this stand 10 turnably around the turning axis. The lances 13, 14 are fitted to the tip part of the arm 12 so as to be freely advanced/ retracted in the furnace 1 and incorporated in the standby position at the side part in the front of the furnace.