To enhance the receiving efficiency of treated raw water of a low concn. by a multiple plate type screw press filter apparatus.

A filter cylinder 2 wherein a large number of annular fixed plates 11 and a large number of annular movable plates 12 are alternately arranged in a superposed state so as to provide fine filtering gaps between the plates 11, 12 is arranged between an inlet chamber 1 for receiving treated raw water and an outlet chamber 3 for discharging a treated cake, and a main screw 5a starting from the interior of the inlet chamber 1 to pierce the filter cylinder 2 over the total length thereof is arranged and the mechanism 14 shaking the movable plates 12 is provided and auxiliary screws 5b are provided at least between the main screw pitches within the inlet chamber 1 to form a screw press filter.