An apparatus for manufacturing an absorbent body, having a recessed form die formed on a predetermined face of a predetermined member, moving in one direction along a moving path along the predetermined face； a duct disposed in a predetermined position in the moving path, discharging a gas including fluid absorbent fibers from an opening section toward the predetermined face, an absorbent body being formed by suction of the gas through intake holes at a bottom section of the form die to stack into the form die the fluid absorbent fibers included in the gas when the form die passes by the position of the duct. A gap is formed between the predetermined face and the opening section of the duct. A gas pressure inside the duct is lower than a gas pressure outside the duct by suction of the gas from the bottom section of the form die. A first wall is outside the duct. The first wall is spaced from a wall of the duct by a first spacing and spaced from the predetermined face by a second spacing. An outside gas flow along a direction intersecting with the predetermined face and an outside gas flow along the predetermined face is made to reach the gap by the first wall.
