To provide a solid-liquid separating device which reduces a water content contained in water-containing solid matter.

This solid-liquid separating device comprises: a separation tower which is composed of a cylindrical part and a circular cone part continuing below the cylindrical part; an inlet which supplies a side wall of the cylindrical part with a gas fluid, containing the water-containing solid matter, approximately in a tangential direction; an internal insertion pipe which is extended downward to the circular cone part from a top part of the separation tower along the central axis of the separation tower in the separation tower for changing the gas fluid to a whirling flow; a drain port which is provided in a bottom of the separation tower, which is fitted detachably with a filter through which substantially only the water content can pass; and an outlet which is connected to the internal insertion pipe and provided in the top part of the separation tower, which feeds out the gas fluid containing the solid matter whose water content is reduced. When the device is installed in an air conveying line, continuing into a dryer, of the water-containing solid matter, a load on the dryer can be lessened. The device serves effectively to dry crushed matter of a resin molding.