Abstract: A fluidized bed combustion apparatus having an upright combustion chamber with a lower end at which a fluidized bed is formed and combustion takes place. First and second upright partitions are provided in the combustion chamber to divide the combustion chamber into a plurality of sections. The first partition divides the combustion chamber into first and second sections which are joined together by a turning space above an upper end of the first partition and the second partition is hollow and has an open, upper end in communication with the turning space to receive a portion of the combustion products therein. The lower end of the second partition is open to supply the combustion products to the fluidized bed.