The invention discloses a beam scheduler and a beam distribution method of the beam scheduler. The invention aims to realize the effective utilization of a particle beam irradiation facility. When an irradiation request is received from one of a plurality of irradiation chambers (A-D) , the beam scheduler (1) in the invention adds maximum allowable waiting time at the end of beam distribution to the irradiation request, adds the irradiation request to the end of a waiting list, judges whether prediction waiting time at the end of distributing beam to one irradiation chamber is beyond the maximum allowable waiting time, brings forwardly the irradiation request in the waiting list when the prediction waiting time is beyond the maximum allowable waiting time, and distributes beam to the irradiation chamber corresponding to the highest-level irradiation request in the waiting list.本發明之目的為謀求粒子束照射設施之有效利用。本發明之射束排序器(1),當從多數照射室(A~D)中之一個照射室收到照射請求時,對照射請求附加到分配射束為止之最大容許等待時間,將照射請求追加至待機列表之順位尾端,判定向1個照射室分配射束為止之預測等待時間是否超出最大容許等待時間,當判定為預測等待時間超出最大容許等待時間時,提前該照射請求在待機列表中之順位,向與待機列表中最高順位的照射請求對應之照射室分配射束。RD...照射請求RC...照射請求RB...照射請求RA...照射請求TD、TC、TB、TA...最大容許等待時間SD、SC、SB、SA...預測所需時間StD、StC、StB、StA...射束分配到各照射室A~D之時點TmD、TmC、TmB、TmA...最大容許等待時間TA~TD結束之時點
