PURPOSE: To obtain a fluidized bed capable of drastically shortening coating process time.

CONSTITUTION: A fluidized bed has a fluidized bed main body coating particles with pultilayer and maintained at high temperature, a particle take-out chamber 6 connecting to the fluidized bed main body, a partition means for connecting or shielding between the fluidized bed main body and the particle take-out chamber 6, a sampling means 5 provided at the tip part with a particle container detachable in the fluidized bed main body through the particle take-out chamber 6 and a replacement gas supply means to supply replacement gas to the particle take-out chamber 6 and the fluidized bed main body. Coated particles are captured in the particle container of the sampling means 5 with the state the inside of the fluidized bed main body is replaced by the replacement gas from the replacement gas supply means, the particle container of the sampling means 5 is withdrawn to the particle take-out chamber 6, the fluidized bed main body and the particle take-out chamber 6 are shielded with a partition means and the coated particles captured are taken out of the particle take-out chamber 6.