A fluidized coating apparatus wherein a rotatable perforated disk 2 is provided at the lower portion of a processing cylinder 1 and perforated disk opening portions 3 are provided in the vicinity of the outer peripheral edge of this perforated disk 2. The ratio of the total opening area of the perforated disk opening portions 3 to an area of an annular slit 8 formed between the perforated disk 2 and the inner wall of the processing cylinder 1 is within the range from 0.2 to 0.6. Each of the perforated disk opening portions 3 is provided with a cover and side walls so that gas is blown out outwardly in the radial direction or obliquely backward with respect to a rotating direction within 30.degree. to the radial direction of the perforated disk.