A particle radiation therapy of this invention includes an accelerator system for accelerating a charged particle beam, and a beam transportation system for transporting a high energy beam outputted from the accelerator to an irradiation position, wherein the beam transportation system is provided with at least one steering electromagnet and at least one beam position monitor corresponding to the steering electromagnet, and the beam position monitor supplies an excited current for correcting the periodically varied beam position to the steering electromagnet.本發明之粒子線治療系統係由用以將荷電粒子射束予以加速的加速器系統、及將從該加速器射出之高能量射束輸送至照射位置的射束輸送系統所構成;該粒子線治療系統係在前述射束輸送系統中具備有至少1個轉向電磁鐵及與該轉向電磁鐵對應之至少1個射束位置監視器,且前述射束位置監視器係將修正週期性變動之射束位置的激磁電流供給至前述轉向電磁鐵。1‧‧‧入射系統2‧‧‧加速器系統3‧‧‧射束輸送系統4‧‧‧噴嘴30、31‧‧‧偏向電磁鐵32‧‧‧四極電磁鐵33a‧‧‧轉向電磁鐵34a、34b‧‧‧射束位置監視器41‧‧‧轉向電磁鐵電源100‧‧‧粒子線治療系統
