PURPOSE: To enable to steplessly and widely control the hot air-blowing-out width of the longitudinally long blowing-out nozzle of a hot air-blowing out cylinder in a hot air-blowing-out device such as an air drier for a cast coater, and not to necessitate a large space on the side of the hot air-blowing-out cylinder on the control.

CONSTITUTION: The hot air-blowing-out device is characterized in that a blowing-out width control cylinder 18 is rotatably fit in the overlapping state with a hot air-blowing-out cylinder 12 into the fixed type hot air-blowing-out cylinder 12 equipped with a blowing-out nozzle 15 long in the longitudinal direction on a part of the peripheral surface, and that the blowing-out width control cylinder 18 has a notch 20 having the circumferential direction widths larger with approaching the center of the blowing-out nozzle 15.