Abstract: An apparatus for carrying out proton therapy on a patient comprises a proton beam guiding device using magnets, quadrupoles, and an end-mounted device for proton beam guiding and control device with an exit window for guiding or directing the proton beam to the treatment spot in the patient. A patient table of the apparatus can be moved in a controlled manner in such a way that the patient can be placed in a desired position with respect to the proton beam. The proton beam guiding and controlling device can be turnably or rotatably mounted around a horizontal axis of rotation in such a way that the patient table which is arranged approximately on the plane of the axis of rotation remains accessible from one side at all moments for the person treating the patient.