A particle beam irradiation system comprising a scanning electromagnet (2) for a particle beam to scan an irradiation object, a scanning information storage section (4) for storing scanning position information regarding a plurality of scanning positions in a case where a particle beam scans an irradiation object and scanning order information which is order for scanning a plurality of scanning positions, and a scanning electromagnet control section (8) for controlling a scanning electromagnet based on scanning position information and scanning order information which is stored in the scanning information storage section, wherein the scanning position information which is stored in the scanning information storage section includes a part whose scanning position information is same as the scanning position information of adjacent order.
