Trailer device

To improve a trailer device for a motor vehicle, 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, into which an insertion portion of a ball neck carrying a coupling ball is insertable and fixable, 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 drive, which is coupled to the ball neck receiving body by means of a coupling unit which has a freewheel and which in particular comprises a plurality of coupling elements.