To provide a penetration member for fire prevention of section that enhances general purposeness and expandability.

Besides a fitting click 2 being formed inside of the end of elastic metal plate which is bent in the section into a C-shape, fitting holes 7 is formed in multi-stage manner, to fit this fitting claw 2. Furthermore, the thermally expanding rubbers 4, 4a are stuck on the inside of both sides of the elastic plate 1, becoming two rows as an example, and the inside slide notch part 6, 6a is formed on one end of the thermally expansive rubber 4, 4a, and the outside slide part 3 is formed at the other end. General purposeness is raised by fitting the pipe of different bore diameter with one member, because the inside diameter of the member can be adjusted in matching with the bore diameter of pipe 8. The expansion performance is also kept high, notwithstanding the adjustment by eliminating the vacant space of thermally expansive rubber 4, 4a, when it is matched to the bore diameter of pipe 8, by forming the notch part to fit each other on both ends of thermally expansive rubber 4, 4a.