Disclosed are a fan motor and a vacuum cleaner which include a blowing fan and a plurality of diffuser blades disposed at a radially outer side of the blowing fan and circumferentially spaced apart from each other. Outer end portions of the plurality of diffuser blades include a spoiler portion formed obliquely to an outward direction with respect to an extending direction of the diffuser blades, so that a flow separation of air flowing across an outer surface of the diffuser blade is reduced. Accordingly, the suction force of the fan motor increases.