The technical purpose of the present invention is to provide a retainer of an alternator for a vehicle to prevent the position separation and rotation from a slip ring end frame. For this, the retainer of an alternator for a vehicle includes a retainer of an alternator for a vehicle which is combined with the slip ring end frame and supports a bearing. The retainer includes a retainer body; and a hollow part which penetrates the center of the retainer body in its length direction. A first surface touching the slip ring end frame in the outer surface of the retainer body is polygonal.
