PURPOSE: To blow hot air uniformly from the whole external periphery into the titled equipment against dispersing air current of granular or powder and to meet the hot air sufficiently and uniformly with granular or powder to uniform heat treating state by guiding the dispersing air current as hollow conical flow, swirling hot air for heating by guide brades and then blowing out the hot air current while compressing the hot air by a controlling means.

CONSTITUTION: Toner particles 3 supplied from a hopper 2 are dispersed with compressed air 4 by an ejector 1 and the dispersing air current 5 is guided to a swirling room 6 and ejected from a swirling nozzle 7 arranged on the lower part into a heat treating room 8 while being turned in the swirling room 6 to form a follow conical flow 9. Against the hollow conical dispersed air current 9, hot air 11 heated by a heater 10 is guided into a hot air swirling room 12 as swirling flow at first and then blown into the room 12 as forward flow, so that the hot air is met or mixed with the dispersed air current 9 uniformly. Cooled air 13 is introduced from an upper wall part into a part close to the inside of the side- wall of the heat treating room 8. The toner sphered in the heat processing room 8 is cooled by cooling air and collected by a cyclone 15 and a dust collector 16 through a discharge port 14.