To provide an inexpensive air-permeable material which is very simply constituted, can be easily manufactured and installed, is rich in general-purpose properties by virtue of few constraints on an installation place, can secure adequate air permeability, and can block intrusion of snow and small animals.

This air-permeable material is constituted by curving and folding an air-permeable plate material 1 like a perforated metal sheet, a mesh, etc., in an expanded U or V shape. Preferably, a fold line 3 is provided on at least one of opposed side surfaces, and a part extending from the fold line 3 to an upper end (a lower end in the case of inverted mounting) is made to abut on a surface wall of an installation part at installation. In addition, a packing material 4 is sometimes anchored to at least one outer surface of the opposed side surfaces, and an incombustible thermal-expansion material is sometimes anchored to at least one inner surface of the opposed side surfaces.