PURPOSE: To know a quantity of pulverized coal accurately and to carry out precise flow control, by obtaining the flow of the pulverized coal through values of a solid and a gaseous phase fluids and a solid-gas ratio.

CONSTITUTION: Inactive gas is sent within a main duct 1 in an arrow direction through pressure by a blower 3. A dumping device of pulverized coal 9 is provided next to a valve 8. A flow signal Q of the inactive gas obtained by an evolution arithmetic unit 6 is multiplied by a constant K by a multiplier 16 depending on necessity and converted into a signal F. A pulverized coal weight signal W obtained from a belt scale 13 and the signal F are applied to a divider 17 and a solid-gas ratio W/F=Z is computed. A signal Qi showing a flow of the pulverized coal 9 is obtained by obtaining a signal ΔPG through correction by the ratio Z of a measured differential pressure signal ΔPtm of a flow meter 25a constituted with a venturi tube. The flow Wi of the pulverized coal is given by Wi=W.Qi/Q. With this, the flow of the pulverized coal can be found accurately and its flow control can be done precisely.