A wiring structure includes a board assembly and pin terminals. In each of pin terminal insertion holes formed in the board assembly, a terminal connection portion electrically connected to a metal foil wire and fitted onto the pin terminal so as to hold the pin terminal is provided in a through-hole of at least one of a plurality of circuit boards forming the board assembly, which forms a part of the pin terminal insertion hole, whereas an insulating sleeve blocking contact between the pin terminal and each of the remaining circuit boards is fitted into through-holes of the remaining circuit boards, which form the remaining part of the pin terminal insertion hole.