PURPOSE: To provide the title duct, withstanding use under wind pressure over a long period and capable of releasing a breeze, by superposing permeable film layers on reinforcing sheets having many ventilating voids to form air- permeable composite layers at least in part of a hollow cylindrical duct.

CONSTITUTION: Many vent holes 3... are bored in a film and the resultant air-permeable film 2 is partially bonded to a reinforcing sheet 4 of nonwoven fabric, etc., having many ventilating voids with an adhesive to form an air- permeable composite layer sheet 5. The sheet 5 is rolled into a cylindrical shape with the reinforcing sheet 4 outside and both side end parts are mutually sealed by fusion. An opening front edge of the cylindrical body is simultaneously closed to constitute the title duct.