To provide a cooling stave with which in the cooling stave for cooling the furnace body in a blast furnace, in he case of eroding cooling piping in the inner part, a dissolution-working can safely and quickly be performed.

In the water supplying piping 13 for supplying the cooling water into the cooling piping 12 in the cooling stave body 11, a first three-way valve 15 is arranged, and in the water exhausting piping 14 for exhausting the cooling water from the cooling piping 12 in the cooling stave body 11, a second three-way valve 16 is arranged, and bypassing piping 17 is set between the first three-way valve 15 and the second cross valve 16. In the case of eroding the cooling piping 12, the outlet from the first three-way valve 15 is changed over to the bypassing piping 17 side and the inlet to the second three-way valve 16, too is changed over to the bypassing piping 17 side and thus, the cooling water is not supplied into the cooling piping 12 so that the cooling water is made to flow through the bypassing piping 17.