To provide a fireproof structural body to be used for penetrating through an opening part of a structural body by a metal pipe which is excellent in processability, can reduce a material cost, and especially, equipped with a firing foamed insulating layer.

A fireproof structural body 1 mainly includes: a fire wall 3 being a dividing part dividing a room or the like; an opening part 5 formed on the fire wall 3; a plurality of continuous bodies 7 installed on the opening part 5; a thermal expandable fireproof material 11b provided so that it encloses the gap between the continuous bodies 7 and the inner face of the opening part 5; and a thermoplastic member 19. A plurality of continuous bodies 7 are inserted through the opening part 5. A receiving member 17 is inserted from one side of the opening part 5. The thermoplastic member 19 is provided so that it is brought into contact with the receiving member 17 in the inside of the opening part 5. The thermoplastic member 19 is such a member that easily burns, melts to disappear or flow out by the heat of firing, for example, a thermoplastic resin (a plastic foamed body) made of high-foaming polyethylene and a rubbery body.