PURPOSE: To prevent the accompanying scattering of a powder, by a method wherein a horizontally arranged long barrel container is formed into a shape having a U-shaped cross area to enlarge the space ratio and the space height therein.

CONSTITUTION: A jacket 52 flowing a heating medium is provided to the outer periphery of a long barrel container 32 with a U-shaped corss area having a power discharge port 42b provided thereto by dirlling and an upper surface cover 22a is mounted to the flange provided to the upper part thereof by a screw. A powder inlet 42a and an exhaust port 42c exhausting steam generated from the powder are provided to the upper surface cover 22a by drilling the container 32 equipped with a vibration generating source 62 is horizontally provided so as to be supported by springs 72a, 72b being an elastomer. The container 32 is vibrated by the vibration generating source 62 while a heating medium is flowed through the jacket 52 and the powder thrown in from the inlet 42a is brought to a certain kind of a floated rotary state in the container 32 to perform drying or reaction treatment.