A method for manufacturing an absorbent body according to the present invention includes a first step of successively introducing an aggregate of absorbent fibers and a water-absorbent resin into a gap that is formed between a first surface and a second surface and is smaller than a thickness of the aggregate of the absorbent fibers, recesses and protrusions being formed on at least one of the first surface and the second surface, a second step of applying a shearing force to the aggregate of the absorbent fibers by moving the first surface relative to and parallel to the second surface in order to mix the absorbent fibers and the water-absorbent resin, and a third step of causing the absorbent fibers and the water-absorbent resin that were mixed to fall, and stacking the absorbent fibers and the water-absorbent resin by suctioning the absorbent fibers and the water-absorbent resin into a recessed portion having a predetermined shape.
