To easily and surely remove the material to be treated depositing on the inner wall surface of the vessel main body of a fluidized-bed treating device or batch mixer and to obvaite the leakage of gas to the surroundings.

A deformable part T using a flexible material is formed at least at a part of the vessel main body 1A in the fluidized-bed treating device 1 or batch mixer to constitute the treating device. The deformable part T is vibrated by the shifter of a cylinder 9 or the like to prevent the deposition and retention of the material to be treated in the main body 1A on the inner wall surface of the main body 1A.