A counter-rotating twin screw extruder includes a motor that generates power through speed reduction of a gear box to directly or indirectly drive two symmetric screw shafts inside an enclosure barrel for synchronous but opposite rotations. Each screw shaft is fit with at least one section of screw and the two screws forms screw flight that are set in opposite directions and alternating each other. The barrel contains therein at least one flow restriction die. A bearing box is set between the barrel and the gear box. The purpose is to reduce unnecessarily induced mechanical energy during the conveyance of material and the advantages of using an independent bearing box are that manufacturing costs are reduced and consumption of energy is cut down. Parts wearing is reduced and durability is enhanced to eventually realize carbon reduction and energy saving.