To prevent backflow of pressure air to the inside of a hopper.

A rotary feeder 3 to take out prescribed quantity of powder and granular material P in a hopper 2 is furnished, an opening and closing valve 9 is provided in a transfer passage of the power and granular material from the rotary feeder 3 to a transport pipe 11, and a transfer passage part between this opening and closing valve 9 and the rotary feeder 3 is formed as a chamber 8A. It is constituted to supply the powder and granular material P1 stored in the chamber to the transport pipe through a screw feeder 10 by actuating the rotary feeder 3 in a state of closing the opening and closing valve 9, supplying the material P in the hopper 2 to a chamber 8A, making the chamber 8A and the hopper 2 in a closed state by a rotor 3 by stopping the rotary feeder 3 thereafter and opening the opening and closing valve 9. Sealing parts 6, 6 free to seal a clearance between an inner surface of a rotor case 4 and an outer surface of a rotor are provided.