A separating device that separates liquid absorbent fibers from a material including the liquid absorbent fibers of an absorbent article and impurities, the separating device comprising: a case; an insertion port for inserting the material into the case, while the material is made to ride on an airflow; a rotation member housed in the case, the rotation member agitating and opening the material; and a discharge port for discharging the liquid absorbent fibers, of the material that has been opened with the rotation member, from inside the case, while the liquid absorbent fibers are made to ride on an airflow, the rotation member rotating around a center axis that has been set with an axial direction along a predetermined direction from the insertion port to the discharge port, the rotation member having protruding sections that protrude outward in a direction that intersects with the center axis in a plurality of positions in the axial direction, a regulating member being provided in a predetermined position between the insertion port and the discharge port in the case, the regulating member regulating movement of the material from the insertion port to the discharge port, wherein the rotation member has a revolving axis and a shaft member, the revolving axis being set with an axial direction along the predetermined direction, the shaft member rotating around a rotating axis that has been set with an axial direction along the predetermined direction, while revolving around the revolving axis, and the shaft member has the protruding sections, characterized in that the rotation member has a plurality of the shaft members arranged in a revolving direction, and each of the shaft members has a protruding section group formed with a plurality of the protruding sections arranged radially in a rotating direction in a plurality of positions in an axial direction of the shaft members. a case; an insertion port for inserting the material into the case, while the material is made to ride on an airflow; a rotation member housed in the case, the rotation member agitating and opening the material; and a discharge port for discharging the liquid absorbent fibers, of the material that has been opened with the rotation member, from inside the case, while the liquid absorbent fibers are made to ride on an airflow, the rotation member rotating around a center axis that has been set with an axial direction along a predetermined direction from the insertion port to the discharge port, the rotation member having protruding sections that protrude outward in a direction that intersects with the center axis in a plurality of positions in the axial direction, a regulating member being provided in a predetermined position between the insertion port and the discharge port in the case, the regulating member regulating movement of the material from the insertion port to the discharge port, wherein the rotation member has a revolving axis and a shaft member, the revolving axis being set with an axial direction along the predetermined direction, the shaft member rotating around a rotating axis that has been set with an axial direction along the predetermined direction, while revolving around the revolving axis, and the shaft member has the protruding sections, characterized in that the rotation member has a plurality of the shaft members arranged in a revolving direction, and each of the shaft members has a protruding section group formed with a plurality of the protruding sections arranged radially in a rotating direction in a plurality of positions in an axial direction of the shaft members.