An electric fan includes a fan base (10), a bearing (40) and a rotor assembly (20). The fan base forms a central tube (11) receiving the bearing therein. The rotor assembly includes a fan hub (22), and a pivot axle (23) joined to the fan hub. The pivot axle pivotably extends into the bearing. A first and second locking rings (50, 70) are received in the central tube. Each of the first and second locking rings defines a central bore (52) therein. The pivot axle is engaged in the central bores of the first and second locking rings. The first locking ring is located at a top of the bearing and the second locking ring is located at a bottom of the bearing to prevent the rotor assembly from escaping from the bearing when the fan is operated.