The present invention relates to a beam therapy apparatus which radiates therapy beam in a pattern to lesions in a patient, and to a method for controlling the same. A beam therapy apparatus according to the present invention comprises: a main body a beam generating unit accommodated in an interior of the main body to generate a therapy beam for treating lesions in a patient a beam delivery unit accommodated in the interior of the main body to guide the beam generated by the beam generating unit from the main body to the lesions in the patient a pattern forming unit which corresponds to the lesion area in the patient and forms a pattern constituted by a plurality of divided cells to which the therapy beam from the beam delivery unit is radiated and a control unit which controls an operation of the beam delivery unit such that the therapy beam may be radiated sequentially or at random to the cells based on the shape of the pattern formed by the pattern forming unit. Thus, the therapy beam may be radiated in a pattern to thereby shorten the time taken for therapy, and the therapy beam can be radiated sequentially or at random to each of the plurality of cells based on the shape of the pattern to thereby prevent a degradation which might destruct cells.La présente invention concerne un appareil de radiothérapie externe, qui émet un faisceau de thérapie selon un motif vers des lésions chez un patient, et son procédé de commande. Un appareil de radiothérapie externe selon la présente invention comporte : un corps principal une unité de génération de faisceau reçue dans un intérieur du corps principal afin de générer un faisceau de thérapie pour traiter des lésions chez un patient une unité de distribution de faisceau reçue dans lintérieur du corps principal afin de guider le faisceau généré par lunité de génération de faisceau du corps principal vers les lésions chez le patient une unité de formation de motif qui correspond à la région de lésion chez le patient et qui
