To easily set initial torque and easily return differential limiting performance even if the performance decreases, by setting an axial adjusting means between a differential case and a case cover.

A pair of disk plates 3 are arranged with facing coaxially each other in a space formed between a differential case 1 and a case cover 2 which blocks its one end, and a ball holder 4 which rotatably holds a lot of balls 5 is placed between both disk plates 3. In the axially facing surface of each disk plate 3, a groove 3b engaging to each ball 5 is provided sequentially circumferentially of each disk plate 3, and when rotational difference occurs for each disk plate 3, each ball 5 is moved along a radial long hole 4c. The differential case 1 and the case cover 2 are assembled by spiraling screws 1e and 2e, its axial position is adjusted, and then, a screw 7 is fastened not to be rotated.