The objective is to eliminate the effect of the hysteresis of a scanning electromagnet so that there is obtained a particle beam irradiation system that realizes high-accuracy beam irradiation. There are provided a magnetic-field sensor that measures the magnetic field of a scanning electromagnet and an irradiation control apparatus that controls the scanning electromagnet based on a measurement magnetic field measured by the magnetic-field sensor and target irradiation position coordinates of a charged particle beam. The irradiation control apparatus is provided with an inverse map means that calculates a target magnetic field, based on the target irradiation position coordinates of the charged particle beam; and a compensator that outputs a control input, to the scanning electromagnet, for controlling the magnetic-field error between the target magnetic field and the measurement magnetic field to be the same as or smaller than a predetermined threshold value.