A rotating irradiation therapy apparatus used for particle beam therapy having a light weight, and having a high positional precision of the applied charged particle beam. The rotating irradiation therapy apparatus comprises a rotating gantry (1) rotatable and equipped with a charged particle beam irradiation device (8) and beam transport devices (9, 10) for guiding a charged particle beam to the irradiation device (8) and a roller (12) in contact with a ring member included in the rotating gantry (1) and supporting the rotating gantry (1). The rotating irradiation therapy apparatus further comprises a front ring (3) disposed in contact with the roller (12) of rotating body support device (16) at one end in the axial direction of the rotating gantry (1), a rear ring (4) disposed in contact with the roller (12) of rotating body support device (16) at the other end in the axial direction of the rotating gantry (1). At least one intermediate ring (5) is disposed in a position different in the axial direction of the rotating gantry (1) between the front and rear rings (3, 4) and in contact with a roller (12) of rotating body support device (16).
