Particles coated with sprayed liquid in a fluidized bed might be kept at relatively high temperature for a long period during drying with high-temperature air. Materials with a low temperature of decomposition should, therefore, be treated for a short time, and hitherto operational conditions have been set empirically. In this study, the relationship among the operational parameters was investigated quantitatively, and the particle temperature was estimated as wet-bulb temperature. It was found that a high coating rate could be obtained from a high feed rate of sprayed liquid and a high temperature or flow rate of inlet air at a given particle temperature.