To greatly reduce ceiling work in piping installation.

The fire spread prevention device includes discharged water collection pipe 2 where at least an outer layer put through the slub 7 of a ceiling 6 is fire-proof, a non-fire proof pipe 4 connected to a joint 14 in the lower part of the discharged water collection pipe 2, an incombustible case member 19 for covering the outer circumference of the non-fire proof pipe 4 including at least the vicinity of the lower end of the discharged water collection pipe 2 in the connection part of the discharged water collection pipe 2 and the non-fire proof pipe 4, a thermal expansion member 20 disposed between the inner peripheral surface of the case member 19 and the outer circumferential surface of the non-fire proof pipe 4 below the lower end of the discharged water collection pipe 2, and a suspension member 21 for supporting the case member 19 on the ceiling 6. The upper part of the suspension member 21 is buried and fixed in a filler 17 filling a gap between the outer periphery of the discharged water collection pipe 2 and the ceiling 6.