4. An apparatus for manufacturing a three-dimensional netted structure having a netted structure being obtained by extruding molten filaments of a thermoplastic resin as a raw material or a main raw material,comprising:a die having a plurality of holes, said filaments being downward from said die; anddrawing-down units partly-submerged in water, having said filaments drop naturally in between,wherein said drawing-down units draw said filaments in between at a speed lower than a filament dropping speed, a distance between said drawing-down units being set smaller than a width of an assembly of said extruded filaments,wherein said drawing-down units are arranged so that four surfaces of the assembly of said filaments contact said drawing-down units before or after said drawing-down units being submerged,wherein a curved plate extends between said die and said draw-down unit thereby introducing said filaments to said draw-down unit, andwherein said curved plate is given at their outer surfaces having a slidability, said curved plate is arranged so that a distance inbetween decreases from upper portions thereof toward lower portions thereof.