PROBLEM TO BE SOLVED: To provide a method of fabricating a separator for fluid catalytic cracker (FCC) apparatuses which enables formation of a clearance between the outermost peripheral ends of a plurality of blades fixed firmly to an inner cylinder and the outer peripheral surface of an outer cylinder, with high dimensional accuracy and uniformity in the circumferential direction.SOLUTION: A method of fabricating a separator for fluid catalytic crackers comprises: forming a lower outer cylinder 18 surrounding blades 14 and an upper outer cylinder 17 joined freely removably with the lower outer cylinder; assembling the lower and upper outer cylinders temporarily to check dimensional specifications of an outer cylinder 11 and dividing again; forming an inner cylinder 12 on the other hand; arranging a ring-shaped jig 20 in the outer periphery of the inner cylinder 12 and joining the blades 14 with the outer peripheral surface of the inner cylinder 12 in a state where individual tips 14b are positioned by the j
