To provide a preferred device configuration and arrangement capable of forming a large irradiation field, miniaturizing a gantry and reducing weight of the gantry. A gantry includes a bending magnet 103 configured to bend a beam orbit, a plurality of horizontal direction scanning magnets 301 and 302 which are first scanning magnets configured to scan the beam orbit in a horizontal direction which is a first direction, and a vertical direction scanning magnet 401 which is a second scanning magnet configured to scan the beam orbit in a vertical direction which is a second direction. The plurality of horizontal direction scanning magnets 301 and 302 is arranged so that θ is equal to or less than 90° when it is assumed that a phase difference between the horizontal direction scanning magnets 301 and 302 is 180n° ± θ. The bending magnet 103 is arranged between the plurality of horizontal direction scanning magnets 301 and 302.
