PURPOSE: To perform a stable supplying of pulverized coal by a method wherein when a relation between an actual mill load and an air flow rate is lost, both an instruction of mill load and an instruction of air flow rate are controlled in such a way that its broken relation is immediately controlled.

CONSTITUTION: A master instruction 14 from an incinerater is fed to a caol feeding machine motor 3 through a manual-automatic change-over unit 15 as a mill load instruction A, the master instruction 14 from the manual automatic change-over unit 15 is fed to a damper driving device 7 as an instruction of air flow rate B. In this control system, the master instruction 14 is fed to the comparation and calculation unit 20 as a comparation signal 19 through a function generator 18 and at the same time a subtractor 21 is arranged and a difference signal 22 from the subtracter 21 is fed to said comparation and calculation unit 20. The comparation and calculation unit 20 compares the comparison signal 19 with the difference signal 22 and when the difference exceeds the specified value, an increased or decreased signal is fed, and fed to an air flow rate control part 36, and when a relation between the mill-load and the air flow rate is lost, an automatic correcting operation is immediately performed to keep a relation between the superior mill load and the air flow rate and to enable a stable supplying of pulverized coal to be performed.