To provide a control method, by which pulverized fine coal level in a coal bin can stably be controlled.

A control unit stores the weighed value of the coal bin at the time of receiving a supply-completing signal as the level after supplying. Then, a discharge-completing signal is received and the weighted value of the coal bin at that time is stored as the level after discharging, and also, the average value of the stored level after supplying and the stored level after discharging, is obtd. and stored as the newest PV value. The four PV values are to be stored containing the one of three times before the newest one, and a coal supplying amount setting value calculating means calculates a coal supplying amount setting value by using three values and the blowing amount of the pulverized fine coal into a blast furnace at the point of time when receiving the discharge-completing signal, and outputs this setting value into a roller mill.