The invention discloses a single-drive double-screw extruder. The single-drive double-screw extruder comprises a barrel body, a first screw, a second screw and a driving device, wherein the first screw and the second screw are arranged in the barrel body. The single-drive double-screw extruder is characterized in that the first screw is fixedly connected with the driving device; the first screw and the second screw are provided with transmission gears which are mutually meshed. The single-drive double-screw extruder disclosed by the invention has the advantages that due to the mutually-meshed transmission gears arranged on the two screws, the purpose that the other screw can also be driven when one screw is driven can be realized; by adoption of the same driving device, the structure of the equipment can be simplified, the energy consumption can be reduced, the rotating synchronization of the two screws is also high, the condition that screw edges of the functional part and a kneading disc are staggered and are butted mutually in a stressing manner can not occur, and the screw edges and the kneading disc are well protected.