PROBLEM TO BE SOLVED: To provide a particle beam irradiation apparatus configured to enlarge angle of visibility in the depth direction and enlarge angle of visibility in the lateral direction, reducing an irradiation error due to displacement of an irradiation target.SOLUTION: A particle beam irradiation unit includes an irradiation nozzle mounted on a rotary gantry rotatable around a horizontal axis to emit a particle beam, and a medical treatment bed rotating the irradiation target around the vertical axis orthogonal to the horizontal axis, wherein when the irradiation target displaces along a predetermined direction, the medical treatment bed rotates the irradiation target so that the predetermined direction is orthogonal to both the horizontal axis and the vertical axis, and the irradiation nozzle applies the particle beam toward the irradiation target from an oblique direction with respect to the predetermined direction.COPYRIGHT: (C)2010,JPO&INPIT【課題】深さ方向の視野角拡大と、横方向の視野角拡大を行なう粒子線照射装置において、照射目標の変位に伴なう照射誤差を小さくする。【解決手段】粒子線照射部は、水平軸線の周りに回転可能な回転ガントリに搭載され粒子線ビームを照射する照射ノズルと、水平軸線と直交する垂直軸線の周りに照射目標を回転可能な治療台とを有し、治療台は、照射目標が所定の方向に沿って変位する場合に、前記所定の方向が前記水平軸線及び垂直軸線のいずれにも直交するように照射目標を回転し、照射ノズルは、前記所定の方向に関して斜めの方向から粒子線ビームを照射目標に向けて照射する。【選択図】図19
