PURPOSE: To enable industrial waste materials to be utilized as the fuel of a fine powder coal boiler by a method wherein the industrial waste materials are supplied to a fine powder coal supplying pipe for a burner and mixed with the fine powder coal.

CONSTITUTION: Fine powder coal fed out together with primary air from a mill 1 are distributed by a distributor 2 and supplied to a burner 4 through fuel pipes 3. In turn, the industrial waste materials 8 are supplied to a fuel pipe 3 from a banker 7 through a feeder 6, mixed with the powder coal within a fuel pipe 3 and then supplied to a burner 4 as the mixture fuel. With this arrangement, it is possible to utilize the industrial waster materials as a fuel without clogging the fuel pipe.