There is provided a particle beam irradiation apparatus in which two or more pairs of scanning electromagnets are utilized so that scanning of a charged particle beam can be performed with a high accuracy and with a high flexibility in the speed, from a low speed to a high speed. In a particle beam irradiation apparatus that scans an incident charged particle beam on X-direction and Y-direction (two-direction) desired orbits perpendicular to the travelling direction of the charged particle beam and irradiates the charged particle beam onto an irradiation subject, there are provided two or more pairs of scanning electromagnets that scan a charged particle beam in the two directions； the desired orbit is given by time-series desired orbit data in which desired irradiation positions corresponding to time are determined； and command values for respective scanning electromagnets in the two or more pairs of scanning electromagnets are generated based on plural pieces of data obtained by frequency-separating the time-series desired orbit data.
