Trailer device

To improve a trailer device for motor vehicles, comprising a holding unit for a crossmember mountable on a vehicle body on the rear-end side thereof and a ball neck receiving body having a ball neck receptacle, in which an insertion portion of a ball neck supporting a coupling ball is insertable and fixable therein, wherein the ball neck receiving body is arranged mounted on the holding unit so as to be pivotable at least between a working position, in which a ball neck is insertable by means of its insertion portion into the ball neck receptacle, and a rest position, it is proposed that the trailer device comprises a locking device which fixes the ball neck receiving body in the rest position in a locking state relative to the holding unit and has an unlocking state, in which the locking device allows the ball neck receiving body to pivot from the rest position in the direction towards the working position, and that an actuator is provided, by means of which the locking device is movable from the locking state into the unlocking state.