The invention discloses a differential gear box and aims to solve the problem that back-twisting state switching of single or more cradles cannot be achieved during cable production in the prior art. The differential gear box comprises a box body, a motor shaft, a pinion, a gearwheel and a worm, the pinion is mounted at one end of the motor shaft, the gearwheel is positioned above the pinion and meshed with the same, the worm parallel to the motor shaft is arranged above the motor shaft and mounted on the box body, the gearwheel is mounted at the left end of the worm, a worm-wheel shaft with an axis perpendicular to the worm is arranged below the worm, a bearing seat is mounted in the middle of the worm-wheel shaft, a worm wheel meshed with the worm is mounted on the bearing seat, and a clutch is arranged at the front end of the worm-wheel shaft. The differential gear box is capable of achieving back-twisting state switching of the single or more cradles without affecting the back-twisting state of other cradles, and capable of meeting requirements on differential motion control in the absence of a planetary gear differential.