To solve a problem wherein operation of a differential lock lever is required for every turn, thereby making operation troublesome, because operation of differential lock release is performed by the differential lock lever to realize a differential condition when a machine body turns and a rotary tilling device is lifted from the ground surface to turn to the right and left in a small working vehicle such as a tiller provided with a differential device conventionally.

The differential device 30 provided between left and right axles 4 of the tiller 1 is constituted in such a way that a fork shaft 43 and a pendulum shaft 51 to which a pendulum 50 is attached are connected through a connection member 45 and the fork shaft 43 is moved by turning the pendulum 50 to perform operation and release of the differential lock so that the differential lock interlocking with the operation for lifting the rotary tilling device 10 when the body turns is released.