A method of manufacturing a scintillator material includes providing a substrate made of a quartz glass and having a recess formed therein; filling the recess with a raw material powder obtained by mixing an iodide raw material and SiO.sub.2 fine particles; after filling the recess, disposing a lid on the substrate to cover the recess; and after disposing the lid, heating the substrate, thereby forming a nanocomposite layer in which an iodide phosphor is introduced into a cristobalite structure.