The invention discloses a machine for the filtering of solid, in particular fibrous, particles suspended in liquids, including a delivery chamber (2) collecting the liquid to be treated, a raceway (3) leading the liquid to be treated into a treatment chamber (4) having a cylindrical bottom (5), wherein there is at least one pair of revolving filters (6, 7), an overflow chamber (16) connected with a recycling tank and an area (21) for the discharge of the recovered solid particles. In the machine each filter (12) has a surface in the shape of a truncated cone and its horizontal axis is essentially perpendicular to the flow direction of the liquid to be treated, the two filters are coaxial with each other and face each other, so as to form a concave space (20) therebetween. The taper of the filters causes the double effect of increasing the filtering performance of the machine and of avoiding its standstill when the delivery of liquid to be treated increases.