PURPOSE: To provide a device permitting the contactless guidance without fluttering of a web, by providing baffles designed as diffusers having at least one stepped part.

CONSTITUTION: Silt-shaped blow nozzles 2, 3 having lips 5, 6 and 7 are formed among molds 9, 10 and 11. The front lips 7, 8 are connected to each other by baffles 12, 13 curved convexly toward a web 1. The baffle 13 existing between the baffle 12 of a rear nozzle 2 and a rear lip 6 of the front nozzle 3 is designed as a shock diffuser. The web 1 is approached to the baffles 12, 13 and shock diffusers 12a, 12b and guided without being brought into contact with them. Since the web 1 is exposed to repulsive and attracting force, the contactless guidance is made possible.