PURPOSE: To provide an inexpensive dust removing apparatus capable of treating a high temp. combustion exhaust gas in high capacity, by a method wherein a rotatable first cylinder is surrounded by an air permeable second cylinder having a screw plate spirally attached to the outer periphery thereof and a heat resistant granular material is filled between both cylinders.

CONSTITUTION: A heat resistant granular material 60 such as sand is thrown in a conveyor pipe 35 from an intake port 36 and sent into a supply chamber 15 through each chute 37. A first cylinder 24 is revolved by a motor 31 and the granular material 60 is moved to the lower end part from the upper end part through a screw plate 25 to be discharged to a discharge chamber 18. Said granular material is further discharged from the outtake port 58 of a conveying-out pipe 53. A combustion exhaust gas enters a lower dust removing chamber 17 from an inflow port 20 and passed through a granular material 60 from the outside lower part of a second cylinder 21 to be introduced into the inside lower part of the first cylinder 24 and further passed to the outside upper part of the second cylinder 21 from the inside upper part of the first cylinder 24 to be discharged to an upper dust removing chamber 16 and guided to an exhaust fan through an outflow port 19. During this time, the granular material 60 is always exchanged.