PURPOSE: To enable adjustment of flow rate of gas passing through a slit formed between a rotary plate and a barrel of a granulating cylinder and a gas passing section of the rotary plate to a wide range, by arranging opening and closing of the slit to be controllable by an expandable slit opening and closing means having a simple structure.

CONSTITUTION: In a device used for granulation, coating, mixing, and drying of powder and granule body, a rotary plate 5 rotating in almost horizontal direction in a granulating cylinder 1 and an expandable slit opening and closing means 17 capable of controlling opening and closing of a slit 16 formed between the periphery of the rotary plate and the inside wall of the granulating cylinder 1 are provided. This means is an expandable hollow tube body contacting with a slit forming face of the rotary plate 5 or the surface of the slit in an expanding stage and positioning on almost the same face as the inside wall face of the barrel part or at the outer side from the inside wall face in the contraction stage. Opening and closing of the slit is performed almost completely with this simple structure and with a simple procedure, and the flow rate of gas passing through the slit and the flow rate of gas passing through the gas passing section are adjusted in a wide range.