An upper insulator and a lower insulator each include extended portions each extending in a circumferential direction near a radially outer end of a corresponding one of teeth. The teeth are each provided with a coil formed of a conducting wire that is wound around the tooth with the upper insulator and the lower insulator in between. The extended portions of the lower insulator each have a guide portion at an edge on a circumferentially outer and upper side near a region where the conducting wire is led from the upper side toward the lower side when wound into the coil.