PURPOSE: To vary a flow distribution effectively in short time by arranging the inner cylinder nozzle having the nozzle aperture of different opening ratio in the peripheral side direction corresponding to the nozzle aperture of the nozzle header opening numerous nozzle apertures in the lengthwise direction of a nozzle and by relatively rotating the outer side and inner cylinder nozzle.

CONSTITUTION: The headers inner cylinder 9 providing the inner cylinder nozzle aperture 11 of different opening ratio in the peripheral direction of the length direction of a nozzle header is inserted into the headers outer cylinder 10 providing a headers outer cylinder nozzle aperture 12. The inner cylinder 9 or outer cylinder 10 is of the structure rotatable with the headers length direction as an axis and the opening ratio is adjusted by rotating. A refrigerant flows into the header inner cylinder 9 from a piping 7, passes through the nozzle aperture 12 of the header outer cylinder via the inner cylinder nozzle aperture 11 and flows out of the header 1. It is made possible to adjust immediately to the proper flowing out quantity even in case of the speed of a strip being varied with the header like this.