FLUIDIZED BED

PROBLEM TO BE SOLVED: To provide a fluidized bed wherein a particulate are fed into the space above a sparger having many micropores, a gas is fed thereto through the micropores from its lower side to thereby effect the contact of the particulate with the gas on the sparger and is made preventive against the adhesion to the micropores of the sparger. SOLUTION: There is provided a fluidized bed being a fluidized bed 1 wherein the shape of at least that part of a micropore 3 of a sparger 2 which lies on the lower gas feed side 13 is that which gradually widens toward the lower gas feed side 13. Desirably, the shape of at least that part of the micropore 3 which lies on the lower gas feed side 13 is a tapered section 15 gradually widening toward the lower gas feed side 13 or a multi-taper or curve 16 in which the angle of widening increases toward the lower gas feed side 13. Part or all of the gas discharged after the contact with the powder or particles 4 on the sparger is recirculated and used again as a gas upwardly fed into the sparger 2.