A method and apparatus for producing multilayer fibrous mats is provided which can form alternate short and long fiber layers continuously on a single forming endless wire cloth. The layers are brought together under the influence of suction air and are held together by interfiber bonds at their interfaces. The apparatus is composed of long fiber defibrators and a short fiber disperser unit placed above the forming endless wire cloth. First, a thin web of long fibers is formed on the forming wire cloth and then a short fiber mat is formed on top of the said long fiber web. At this point, the short fibers to a certain extent are pulled into and among the long fibers of the thin long fiber web by the use of suction air thus forming a long fiber layer, long-short fiber interface layer and a short fiber layer mat construction.