The invention discloses a vacuum extruder with herringbone gears, comprising a motor, a transmission mechanism and an operating mechanism, wherein the output shaft of the motor is connected with the input shaft of the transmission mechanism, and the output shaft of the transmission mechanism is connected with the operating mechanism. The vacuum extruder is characterized in that at least one pair of transmission gears of the transmission mechanism is the herringbone gears. The above technical scheme has the following technical effects: helical gear transmission in the prior art is characterized by meshing by one pair of gears, but the herringbone gear is characterized meshing by two pairs of gears; under the condition that other technical parameters are constant, driving torque distributed to each pair of gears is lowered by half, thus greatly improving the stressing condition of each pair of gears, improving the service life and lowering the possibility of faults, such as snaggletooth and the like; gear contact ratio is doubled to ensure stable transmission and improve whole machine operation performance. In addition, because the axial dip angles of the herringbone gear on the transmission shaft are same but have different directions, axial force mutually offsets, therefore, the stressing condition of the transmission shaft is improved, and the service life of the bearing is prolonged.