To provide a differential gear device which is inexpensive, lightweight and compact as requested by a senior car or the like, and effective for the senior car and having a function capable of preventing stall caused by the idling of wheels by building a power blocking mechanism therein.

The differential gear device comprises an input side member for inputting the rotational torque, an output side member for outputting the torque, and an elastic member in which a plurality of steel balls are arranged therebetween to agree the centers of rotation with each other, a plurality of engaging elements are arranged between both members, the steel balls and the engaging elements are held by a holder, a plurality of cam faces are provided for wedge-engaging both, and the engagement pieces are placed at the neutral position of the cam face in a natural state. Wheels on the side of the slow speed are driven during the traveling state by performing the wedge-engagement of the engaging elements by using an external force applied between both members and a viscous resistance applied to the holder, or using a clutch losing the lock function, and any stall of a senior car is prevented by transmitting the rotational torque to other wheels when the driving wheels are in an idling state. When the car is parked, the rotation of the holder is stopped by a braking plate, and the power is reliably blocked in the differential gear device to enable the hand-push travel.