The particle beam irradiation apparatus comprises: a position monitor that detects a passing position of a charged particle beam; and an irradiation control apparatus that calculates a distance from a predetermined reference point to the position monitor, calculates a beam irradiation position on an irradiation subject, and controls irradiation of the beam; wherein the irradiation control apparatus includes a position calculation apparatus that calculates the beam irradiation position, based on a beam position detected by the position monitor, a scanning starting point distance information on a distance from a irradiation plane of the irradiation subject to a scanning starting point, of the beam, in a scanning electromagnet, and a position monitor distance information on a distance, from the irradiation plane to the position monitor, that is calculated based on the calculated distance.