An apparatus for manufacturing an absorbent body of an absorbent article by depositing a liquid absorbent material on an air-permeable member by passing an air that contains the liquid absorbent material in a thickness direction of the air-permeable member, the apparatus including: a plurality of plates that are stacked in the thickness direction, that constitutes the air-permeable member, each of which includes a plurality of air holes that penetrate the plate in the thickness direction and that allow the air to pass, and each of which includes a joining portion for joining to an adjacent plate in the thickness direction in a portion of the plate in which the air holes are not formed, the plurality of air holes of each of the plates being arranged so as to communicate with corresponding air holes of an adjacent plate in the thickness direction, corresponding air holes of all the plates stacked in the thickness direction having a same shape.