Abstract: A granulating and coating machine for use in granulation, coating, mixing, drying etc. of powdery or granular materials. The machine includes a casing for holding the powdery or granular raw materials, a rotator for performing granulation or coating arranged at the bottom of the casing and formed with at least one ventilating porition, an annular slit formed between the periphery of the rotator and the inner wall of the casing. A gas flow adjusting mechanism including two separated ducts for gas flow is provided in order to control independently the rate of gas fed through the ventilating portion and the slit gas fed through the slit. An agitator for agitating the powdery or granular materials and a disintegrator for breaking undesirously large particles of the powdery or granular materials may be provided above the rotator. The slit may be formed by an annular slit forming ring mounted on the inner wall of the casing.