The objective of the present invention is to deliver a charged particle beam whereof the variation in the number of particles at the edge portions follows a smooth distribution, without causing the beam size to become unnecessarily large. The beam delivery system (30) is equipped with a beam shaping device (10) comprising: a pre-stage quadrupole electromagnet (3) for reducing the width of the distribution of an x angular component (x), which is a slope in an x direction relative to the progression direction of the charged particles in the beam, wherein the x direction is a direction that is orthogonal to the progression direction of the charged particle beam, originates from the beam center, and traverses an abrupt edge portion a penumbra enlargement device (1) for smoothing the shape of the edge portions in the particle number distribution of the x angular component (x) in the beam that has passed through the pre-stage quadrupole electromagnet (3) and a post-stage quadrupole electromagnet (4) for adjusting the betatron phase in the phase space distribution in the x direction of the beam that has passed through the penumbra enlargement device (1). The post-stage quadrupole electromagnet (4) adjusts the phase lead angle of the betatron phase from the penumbra enlargement device (1) to the isocenter (IC) in a range of an odd multiple of 90 degrees ± 45 degrees.Lobjectif de la présente invention est de fournir un faisceau de particules chargées, dont la variation du nombre de particules au niveau des portions bords suit une distribution régulière, sans faire en sorte que la taille du faisceau devienne inutilement grande. Le système de fourniture de faisceau (30) est équipé dun dispositif de formation de faisceau (10) qui comprend : un électro-aimant quadripolaire de pré-étage (3) pour réduire la largeur de la distribution dun composant angulaire x (x), qui est une pente dans une direction x par rapport à la direction de progression des particules chargées dans le faisc
