A holder 20 has a holder side wall 22 provided with a through hole 26, while an outer peripheral extension 43 of a lightguide 40 is inserted through the through hole 26. Therefore, even when the holder 20 is a “hollowed integral holder” formed integrally with a design panel 60, the lightguide 40 comprising a ring part 41 and the outer peripheral extension 43 can be assembled to the holder 20.