During sending the combined body 47 to the core member 6, the pre-orientation members 81 are respectively inserted into a plurality of the consecutive clearances 472 of a plurality of the clearances 472 formed between the adjacent straight overlap sections 471 of the combined body 47. By the pre-orientation members 81, the overlap of the straight portions 431 in the straight overlap section 471 and the pitch between the straight overlap sections 471 are aligned in advance.