PURPOSE: To constitute the title mouthpiece so as to enable adjustment of not only flow resistance of a raw material but also external dimensions of a latice structure, partial fine adjustment of the flow resistance and application to a latice structure even if a section of a radial direction is in a form other than a round external form.

CONSTITUTION: One end is provided with a latice structure molding flow path, the other end is provided with a raw feed flow feeding the raw material of the latice structure and the latice structure molding flow path possesses the outermost wall molding flow path 6 molding the outermost wall of the latice structrure. A plurality of outer circumferential rib flow rate control plates 10 whose tip part has an acute angle are provided on an end part of a downstream side of the latice structure molding flow path, the outer circumferential rib flow rate control plates 10 each move in a diametral direction of the outermost wall molding flow path 6 respectively independently by a control plate adjusting screw 11 and an external circumferential surface side 15 of the outermost wall molding flow path 6 is drawn.