The present invention is a separation device that separates liquid-absorbing fibers from a material having a contaminant and the liquid-absorbing fibers, which pertain to an absorbent article. The present invention has: a case an introduction opening through which the material is introduced into the case while riding on a flow of air a rotating member that is housed in the case and that agitates and opens the material and a discharge opening that causes the liquid-absorbing fibers from the material opened by the rotating member to ride on an a flow of air and to be discharged from the interior of the case. The rotating member has: a revolving shaft set in a manner such that the axial direction thereof is along a predetermined direction oriented from the introduction opening to the discharge opening and a shaft member that, while revolving around the revolving shaft, rotates around an axis of rotation resulting from setting the axial direction thereof along the predetermined direction. The shaft member has a protruding section that protrudes outwards in a direction intersecting the axial direction of the shaft member.
