This invention provides a fluoride sintered compact for neutron beam moderator, the fluoride sintered compact is suitable for a moderator that decelerates neutron radiation to generate therapeutic neutron beam which is used for irradiating the affected area of deep part of body to destroy tumor； the fluoride sintered compact is composed by MgF2 of precise polycrystalline structure, having the following mechanical strength: bulk density is 2.90g/cm3 or more, bending strength is 10 MPa or more, Vickers hardness is 71 or more.本發明提供一種燒結體，係適合於能夠使高能量中子射線減速，生產照射身體深處之患部，消滅腫瘤之治療用中子射線等減速材料之氟化物燒結體，由緻密的多結晶構造之MgF2構成，堆密度為2.90g/cm3以上，彎曲強度為10MPa以上，具有維氏硬度為71以上的機械強度之中子射線減速用氟化物燒結體。
