PURPOSE: To continuously supply waste matters and discharge solid matters contained in the waste matters and perform highly efficient solid-liquid separation, by compressing and squeezing waste matters fed between an upper and a lower endless filter cloth through a frame plate conveyor.

CONSTITUTION: When a waste matter is fed to a lower filter cloth (b) from a location shown by an arrow (c) at the left hand side, the waste matter put between filter cloths (a) and (b) is compressed against a lower frame plate conveyor 17, and the filtrate flows into a filtrate recovery hopper 56 through holes of butt straps and the solid matter is deposited between the upper and lower filter cloths (a) and (b). As the filter cloths (a) and (b) run at the same speed as frame plate conveyors 20 and 17 run, the waste matter is gradually dehydrated, and the filter cloth (a) turns upward at an upper guide roll 43 and the filter cloth (b) turns downward at a lower guide roll 47. As the filter cloths are separated from each other by means of the guide rolls 43 and 47, the solid matter between the filter cloths (a) and (b) is exfoliated from the filter cloths (a) and (b) and falls down.