Abstract: A filter block for filtering melt synthetic plastic materials in a process of manufacturing plastics filaments includes a plurality of layers of wire fabric arranged in superimposed relationship. From the top to the bottom the filter block comprises inlet layers, intermediate layers and outlet layers. All the layers of the intermediate portion of the filter block are of identical mesh size which is smaller than mesh size of the inlet and outlet layers. The filter block is produced by cold forming exclusively in a stamp provided with an elastic suport for a pressure plate on which filter layers to be compressed are positioned and with a rigid support, which elastic support and rigid support operate successively to obtain inlet, intermediate and outlet filter layers of differing porosity.