To provide an instrument for preventing the spread of a fire, capable of effectively preventing a fire from spreading in the early stage of the fire caused by oil leakage.

The instrument is connected to a high-pressure water supply source (2), divides a fire disaster prevention object area (4) and a fire disaster area (5) and forms an induction area (7) continuous to the fire disaster area (5). The instrument is constituted of a freely deformable and long cylindrical body (1) to which no waterproof lining is provided and in which water permeation seeps out from the wall surface (1c). The cylindrical body (1) has a straight form and can be the one with one end (1a) closed, wherein the closed one end (1a) can be freely connected and communicated with the end of other cylindrical bodies. The cylindrical body (1) includes an annular part (1d) that is freely opened/closed and a straight part (1e) that extends from the annular part (1d). The open end of the straight part (1e) can be freely connected to the high-pressure water supply source (2).