[Problems to be Solved] A neutron scintillator excellent in detection efficiency for neutrons, an S/N ratio, and n/γ discrimination ability, and a eutectic preferred for the neutron scintillator are provided.[Means to Solve the Problems] A metal fluoride eutectic, in which a lithium fluoride crystal phase and a crystal phase represented by the chemical formula Ca1-xSrxF2 (where x denotes a number greater than 0, but not larger than 1), such as SrF2 or Ca0.5Sr0.5F2, are present in a phase-separated state; a neutron scintillator comprising the eutectic; and a neutron imaging device comprising a combination of the neutron scintillator and a position-sensitive photomultiplier tube.