A kneading extruder includes a barrel having an extrusion port through which kneaded material including first and second liquid raw material is extruded, and a screw shaft placed in the barrel, the screw shaft kneading the first and second raw material to produce the kneaded material in melted state. A screw driving device continuously rotates the screw shaft at a constant speed, and a die communicates with the extrusion port of the barrel, the die having an extrusion port through which the kneaded material in a pressurized state is extruded. An ejection device ejects a portion of the kneaded material between the extrusion port of the barrel and the extrusion port of the die, the ejection device including an ejection quantity regulating unit for regulating the ejection quantity of the kneaded material so that the pressure of the kneaded material at the extrusion port of the barrel is kept constant.