An apparatus of the present invention is a continuous extrusion forming apparatus comprising: a screw which carries a forming raw material in the horizontal direction, the screw being built in the screw part; and a mouth piece structure for extrusion forming, which is provided on the downstream side of a screw part, wherein the mouth piece structure has a horizontal channel for extruding the forming raw material flowing in from the screw part in the horizontal direction, an extrusion channel orthogonal to the horizontal channel, and an extrusion port provided at a tip end of the extrusion channel, and wherein a mouth piece structure holder which holds the mouth piece structure is provided with a turning means which freely changes the opening direction of the extrusion port between the horizontal direction and a floor facing direction.