Abstract: The stand-up unit comprises a support a stand-up frame, which is articulated on the support and has a seat carrier carrying a seat, and a backrest carrier carrying a backrest. Furthermore, a first lever parallelogram is provided in order to maintain the backrest upright in any position. The backrest can be displaced by the first lever parallelogram by means of a rod, in order to ensure that no undesirable relative movement occurs between the backrest and the back of the user when getting up or sitting down. A second lever parallelogram controls the movement of the seat when getting up and sitting down to ensure that no relative movement develops between the seat and buttocks of the user. The stand-up unit may be provided with a base to serve as a chair, particularly a therapy chair. The stand-up unit, however, may also serve as a stand-up wheelchair, when connected to an undercarriage. Spring joint elements support the standing up.