To prevent the breakage of a valve body by arranging an expansion at the front and the rear parts of the valve body in a blast branch tube arranging a hot blast control valve provided with the ceramic-made valve body to absorb the thermal expansion and break with the vibration.

Hot blast is supplied to a tuyere 4 through a hot fluid flowing passage 13 formed by arranging a nozzle 2 as the blast branch tube of a hot blast annular tube 1 of a blast furnace and arranging a fire insulating layer 12 on the inner wall of the metal-made casting 11. Further, in the flowing passage 13, the ceramic-made valve body 14 is arranged so as to be freely opened/ closed. In this hot blast control valve 10, the valve body 14 is rotated with a driving motor 20 and also, supporting shafts 17, 18 and a bearing 24 are cooled with a cooling mechanism 19 to prevent the burning, and the dust purge is executed through inert gas supplying mechanisms 28, 29. In the hot blast control valve, the expansions 21, 22 composed of bellows expansion joints are arranged at the front and the rear parts of the valve body 14. It is desirable that this bellows can supply the cooling water 32 between thin plates 30, 31.