The upper drawing in FIGS. 18A and 18B is a side view of the center core 58 and the second magnetism shielding plates 90A. The lower drawing in FIGS. 18A and 18B is a bottom view of the center core 58 and the second magnetism shielding plates 90A. In FIGS. 18A and 18B, an outer surface of the center core 58 (magnetic tube 582) is indicated with a hatched region.