A radiotherapeutic device (1) comprises a guide (9) for moving a radiation generator (4) along a path of predetermined radius so that the X-rays (Ri) emitted by the radiation generator (4) may cross an isocenter (13), and a support member (12) for rotating the guide (9) around the axis of an inclined shaft (11) extending through the isocenter (13). The radiation generator (4) is moved along a spherical surface by the guide (9) and support member (12) to radiate X-rays (Ri) toward the isocenter (13) from many directions.
