[PROBLEMS] A solid-liquid separation device having a solid-liquid separation section provided with adjacent stationary plates and movable plates arranged between the adjacent stationary plates and also having at least one screw extending so as to penetrate the solid-liquid separation section. The movable plates are formed such that they are pushed and moved by the screw that rotates.An object to be processed having entered in the solid-liquid separation section is moved toward the exit of the solid-liquid separation section, and at the same time, filtrate separated from the object is discharged to the outside through a filtrate discharge gap of the solid-liquid separation section. Wear of the movable plates are suppressed with dewatering efficiency for slurry maintained at a high level. [MEANS FOR SOLVING PROBLEMS] The diameter (d) of the shaft (41) of a screw section (21A) on the exit side of the solid-liquid separation section (3) gradually increases from a predetermined position (S 1 ) of the screw in the solid-liquid separation section (3) toward the exit side, and the lead angle of the screw section (21A) is set to the range from 10° to 30°.