To provide a construction method for forming a through-hole on a housing of a wall or a floor or the like comprising ALC.

To a lower hole formed through an ALC panel P, a first sleeve tube 2 with a flange part 5 to be abutted to a wall surface formed at the proximal end part is inserted and fitted to one opening of the lower hole H, and a second sleeve tube 3 with a flange part 8 to be abutted to the wall surface formed at the proximal end part is inserted from the other opening of the lower hole H. At least one of both sleeve tubes 2 and 3 comprises a fire-resistant thermal expansion material. By screwing the part near an insertion destination of the second sleeve tube 3 to the part near the insertion destination of the first sleeve tube 2, the ALC panel P is clamped by the flange parts 5 and 8 of both sleeve tubes 2 and 3.