To provide a ventilation layer forming member which can preliminarily keep its width at a predetermined value in accordance with the arrangement pitch between rafters, which can be prevented from sagging by itsself-weight, to the utmost, and which is excellent in mounting workability. 垂木間の配設ピッチに合わせて、その幅を予め所定値に保持し得、かつ自重での垂れ下がりも可及的に防止し得る、取付作業性に優れた通気層形成部材を提供する。 - 特許庁