The invention relates to a hadron therapy installation that comprises an irradiation unit (1) supported by a rotary support structure, so as to be able to rotate around a target volume (15) centered on the axis of rotation (22), to deliver a treatment beam (17) from different angles on the target volume (15). An imaging device (3, 4) is secured in rotation with the irradiation unit (1) and translatable relative to the irradiation unit (1) between a retracted position at the irradiation unit (1) and a lateral deployed position relative to the target volume (15), such that in its deployed position, the imaging device (3, 4) can rotate around the target volume (15) together with the irradiation unit (1). Such an installation can be used for a cone beam computed tomography method and/or a fluoroscopic imaging method on a patient to be treated in the hadron therapy installation.