An automotive alternator in which a fan rotating together with a rotor to direct air from a suction aperture into a case, blow the air centrifugally, and discharge the air externally through a discharge aperture has a blade including an interposed portion extending axially from an end surface of a pole core between an adjacent pair of claw-shaped magnetic poles. For this reason, cooling of a rotor coil and a stator coil is improved by improving capacity of the fan in a limited space, thereby enabling output to be improved.