To efficiently exhibit fireproof performance when filling inside a penetrating section with a thermal expansion fireproof filler.

Even when a plurality of conduit pipes P are moved while a thermal expansion fireproof filler 31 is cured, a fireproof sheet 11 is interposed between the conduit pipes P and a through hole Wa, and a fireproof sheet 21 is interposed between the conduit pipes P. Thereby, even when the conduit pipes P are moved by the time the thermal expansion fireproof filler 31 is cured, and a sufficient amount of thermal expansion fireproof filler 31 is not disposed between the conduit piles P and the through hole Wa and between the conduit pipes P, the fireproof sheets 11 and 21 function as the thermal expansion fireproof filler 31, with the fireproof sheets 11 and 21 interposed therebetween. Thus, even if the thermal expansion fireproof filler 31 is compressed by the conduit pipes P, when the through hole Wa is filled with the thermal expansion fireproof filler 31, efficient fireproof performance can be exhibited inside the through hole Wa.