A treatment device for medical and/or cosmetic therapy includes a negative-pressure chamber receiving a lower half of a person's body. The negative-pressure chamber is designed as a tube and has an admission opening sealed off from the person's body by a closure element. A first part of a table is arranged in the interior of the negative-pressure chamber. A second part of the table is arranged outside the negative-pressure chamber. The first part and the second part are each guided longitudinally on a linear guide. The first part can be moved at least partially out of the negative-pressure chamber and the second part can be moved away from the admission opening. A synchronization between the first part and the second part allows the first and second parts to be moved at the same speed in the same direction.