PURPOSE: To simply, cheaply execute the coating for granules, etc., by partitioning the outside of the rotary drum, being drafty and provided with internal spray nozzle, into the influent air duct and effluent air duct, and by suitably arranging the hot air feeder, the air exhauster, the product discharger, etc.

CONSTITUTION: The material is charged from the opening 3 of the perforated cylindrical drum A being rotated by the rotary shaft 5, and the coating agent is sprayed from the nozzle 24 being supported by the parts 25 installed in the shaft 5; at the same time, the hot air is sent to the outer duct 10 of the drum A being divided by the partition 11, through the heater 19, the blower C, and the air duct 13. The hot air dries the material falling from the agitating parts 8 of the drum A, and is exhausted through the duct 9 and the exhaust pipe 12. After the drying is finished , the rotary shaft 5 is pulled up, and the opening 3 of the drum A is turned to look down, and the product is discharged. The covers 33, 34, installed in the outside of the drum A, together with the duct 9 are utilized as the reservoir of the wash water for the drum A, and also as the heat insulators while the period of coating work.