A method for manufacturing an alternator includes preparing a wire-strand group formed by bending strands of wire so as to have straight portions which fit into slots, forming a base core by laminating plate-shaped magnetic members formed with the slots, stacking the wire-strand group on the base core and pressing the wire-strand group such that the straight portions enter the slots, and forming the stator core by bending the base core into a cylindrical shape and abutting end surfaces of the base core.