PURPOSE: To facilitate exchanging, increasing and decreasing a combustible lengthy body by forming an enlarged diameter portion, inside of which a heat foaming refractory material is stored, in a part of a fire resistance pipe in its longitudinal direction and making the inside diameter of the heat foaming refractory material approximately the same or larger than that of the non-enlarged diameter portion of the fire resistance pipe.

CONSTITUTION: A fire-protection pipe 11 is formed with an enlarged diameter portion 15 in the midway of a metal pipe 13 with a heat foaming refractory material 17 stored inside the enlarged diameter portion 15. The inside diameter of the heat foaming refractory material 17 is made approximately the same as that of the non-enlarged diameter portion of the metal pipe 13 in the state of the heat foaming refractory material 17 stored in the enlarged diameter portion 15. For example, the fire protection pipe 11 is connected to the midway of a pipe conduit 19 using a pipe fitting 21 and a plastic covered conductor 23 is drawn into a conduit run composed of the pipe conduit 19 and the fire protection-pipe 11. In case fire brakes out at the right side of the fire protection-pipe 11 and the conductor 23 starts burning, the heat foaming refractory material 17 foams, swells and fills up the fire protection-pipe 11 when the spread of the fire burning the conductor 23 reaches near the foaming refractory material 17 and thereby checks the spread of the fire to the conductor 23.