It is provided an adjusting device for a seat element of a vehicle seat supporting a body part of a seat user, with at least one driving device comprising a spindle drive and at least one adjustable support element for changing the contour or position of the seat element, wherein the spindle drive comprises a spindle extending along a spindle axis, which is floatingly mounted at a spindle end via a spindle holder such that at this spindle end the spindle is displaceable along at least one spatial direction extending transversely to the spindle axis. The spindle holder comprises a first and a second compensating element for a displaceability of the spindle end with respect to two first and second spatial directions extending approximately perpendicularly to each other and each perpendicularly to the spindle axis.