PURPOSE: To obtain a H-beam free from a web wave and a flange warping by jetting cooling water on the outside surface of a flange, the mixture of air and water on the inside surface of the upper half of the flange, and cooling water on the boundary part of the flange and the web, further absorbing staying water on the upper surface of the web.

CONSTITUTION: The outside surface of a flange, is cooled by cooling water from a cooling water jetting nozzle 11. At the same time, the supporting roller 15 of the inside surface of the flange, is allowed to come into contact with the inside surface of the flange. At the same time, the atomization nozzle 16 of the mixture of air and water for cooling the inside, and the cooling water nozzle 17 of a R part, are aligned with prescribed positions, and the inside surface of the flange, is cooled by jetting cooling water or the mixture of air and water from respective nozzles. Since cooling water stays on the upper surface of the web, the staying water on the web surface, is sucked by a water absorbing means 18 to prevent excessive cooling. Also, in regard to the bottom surface of the flange, a support 19 with the atomization nozzle 16 of the mixture of air and water and the cooling water nozzle 17 of the R part mounted, is moved in the perpendicular direction of a line, it is also ascended, and positioned cooling is performed.