PURPOSE: To obtain coke of having uniform coke strength and high quality by charging coal containing briquett having excellent coking properties from outside charging port in the direction of furnace length and charging coal containing briquett having inferior coking properties from inside charging port.

CONSTITUTION: Charging coal 4 mixed with briquett having small inviscid coefficient and excellent a coking property is received in coal-charging hoppers 1-1 and 1-4 outside of a coke furnace 2 in the furnace length direction and charging coal 5 mixed with briquett having large inviscid coefficient and a coking property inferior than the above-mentioned briquett is received in coal-charging hoppers 1-2 and 1-3 inside. Then, the briquetts are thrown from respective hoppers to charge the charging coal 4 to furnace cover side of carbonizing chamber and the charging coal 5 to inside of the carbonizing chamber.