PURPOSE: To prolong the life of stave coolers and to maintain the cooling function of the body of a blast furnace by forming cooling pipes of the stave coolers as double pipes and making the supply of water into the inside and outside pipes free.

CONSTITUTION: The cooling pipes 2 to be contained in bodies 6 of stave coolers are constituted of double pipes consisting of inside pipes 3 and outside pipes 4. A cooling water supply pipe 7 is branched at the inlets of the stave coolers; one thereof is connected to the pipe 3 and the other to the pipe 4, and are made respectively freely communicatable with only the pipe 3, only the pipe 4, or both of the pipe 3 and the pipe 4 through a 3-way valve 10 or the like. With such mechanism, even if the pipe 4 is ruptured, the valve 10 is operated to supply the cooling water only in the pipe 3, whereby the cooling effect is maintained; at the same time, shapeless refractory materials, etc. are forced into the ruptured pipe 4 to protect the pipe 3.