PURPOSE: To improve combustion efficiency, work environment, and safety, by a method wherein a powdery combustion substance is mixed in a bonding material to produce conglomerate, which is charged in a fluidized bed.

CONSTITUTION: Coal 11 is received in a coal storage silo 10 once, is quarried out by means of a quarrying machine 12, and is graded by means of a vibration sieve 13. Sieved coal is scattered over the whole surface of a fluidized bed 4 through a seal device 17 by means of a scattering machine 18. Pulverized coal sieved by the sieve 13 is conveyed to a mixer 20, water or other like binder 22 is added as the pulverized coal is agitated by a mixing screw 19, they are mixed and humidified to produce conglomerate, which is dropped onto a fluidized bed 4 through an opening part formed in the cooling water pipe wall of the ceiling part of a furnace. The charged humidified and conglomerated pulverized coal is dropped onto the fluidized bed 4 and enters the bed. A moisture content is vaporized through heat exchange with a fluidizing fluid medium, and the pulverized coal is brought into a powdery state again in the bed as a bonding material component is lost by combustion and volatilization. But, it is already brought into an ignition state, it is well burnt off until it is discharged from a free port 5, unburnt loss is almost prevented from incurring, in-furnace combustion efficiency is improved, and a risk, e.g., coal dust explosion, is eliminated.