Provided is a beam shaping body (60, 70) for neutron capture therapy that improves the radiation flux and quality of a neutron source. The beam shaping body (60, 70) includes a beam entrance (61, 71), a target (62, 72), a speed reduction body (63, 73) adjacent to the target (62, 72), and a speed reduction body (63, 70). 73) is disposed in the reflector (64, 74), the thermal neutron absorber (65, 75) adjacent to the moderator (63, 73), and the beam shaping body (60, 70). A radiation shield (66, 76) and a beam outlet (67, 77). Neutrons are generated by the nuclear reaction between the target (62, 72) and the proton beam incident from the beam entrance (61, 71), and the neutron beam is formed by the neutron, and the neutron beam defines one main axis (X6, X7). The neutron from the target (62, 72) is decelerated to the epithermal neutron energy region by the moderator (63, 73), and the moderator (63, 73) includes at least one tapered shape. The speed reducer (63, 73) has a main body part (631, 731) and a supplement part (632, 732) surrounding the outer periphery of the main body part (631, 731), and the supplement part (632, 732). ) Is different from the material of the main body (631, 731), and the reflector (64, 74) mainly uses neutrons deviated from the main axes (X6, X7) to increase the epithermal neutron beam intensity. The thermal neutron absorber (65,75) leads to (X6, X7) and is used to absorb thermal neutrons in order to avoid excessive doses to normal tissues on the surface during treatment, and radiation shields (66,76) Is used to shield leaked neutrons and photons to reduce the dose to normal tissue in non-irradiated areas.中性子源の放射フラックスと品質を向上させる、中性子捕捉療法用ビーム整形体（６０，７０）を提供する。ビーム整形体（６０，７０）は、ビーム入口（６１，７１）と、ターゲット（６２，７２）と、ターゲット（６２，７２）に隣接する減速体（６３，７３）と、減速体（６３，７３）の周囲に配置される反射体（６４，７４）と、減速体（６３，７３）に隣接する熱中性子吸収体（６５，７５）と、ビーム整形体（６０，７０）内において設置されている放射線遮蔽体（６６，７６）と、ビーム出口（６７，７７）とを備える。ターゲット（６２，７２）とビーム入口（６１，７１）から入射した陽子ビームとの原子核反応により中性子が生成され、中性子により中性子ビームが形成され、中性子ビームは一つの主軸（Ｘ６，Ｘ７）を規定し、減速体（
