PROBLEM TO BE SOLVED: To provide an accelerated particle beam irradiation facility in which a particle beam accelerator and an irradiation device can be efficiently installed in a predetermined site.SOLUTION: A particle beam treatment facility for irradiating a patient with a proton beam comprises: a cyclotron 2 for generating the proton beam a rotary gantry 3 including an irradiation unit for irradiating the patient with the proton beam a guide line 4 for guiding the proton beam generated by the cyclotron 2 to the rotary gantry 3 and a building 6A having a hierarchical structure of a plurality of floors. The building 6A includes: a cyclotron room R1 in which the cyclotron 2 is installed and a gantry room R2 in which the rotary gantry 3 is installed, the gantry room being provided on a floor higher than a floor on which the cyclotron room R1 is provided. The gantry room R2 has an aperture 92 for carrying in a component of the rotary gantry 3, the aperture being formed on a ceiling 86 of the gantry room. The aperture 92 is covered with a shield member 93 for intercepting a radiation ray.SELECTED DRAWING: Figure 1
