Among other things, an applicator means (20) for x-ray radiation therapy for the irradiation of surfaces, as well as a radiation therapy device are described, having an applicator element (21) for taking up a probe tip or a radiation source element of a radiation source means (11). In order to further develop applicator means (20) in such a way that it is especially suitable also for the irradiation of surfaces, it is provided that applicator element (21) for adjusting different beam characteristics has at least one element (27) for influencing the beam, in particular a lens element, which is disposed in an exchangeable manner at/in applicator element (21). In addition, an advantageous fastening means is described, by means of which applicator means (20) can be attached and fixed on the surface to be treated.