A layered three-dimensional radiation position detector includes two-dimensional scintillator arrays that are pixelated by optically discontinuous surfaces and stacked on a light receiving surface of a light receiving element, responses of scintillator elements detecting radiations being made identifiable on the light receiving surface to obtain a three-dimensional radiation detection position. A scintillator array lying on a radiation incident surface side has a pixel pitch smaller than that of a scintillator array lying on a light receiving element side so that the scintillator array on the radiation incident surface side has increased resolution. A layered three-dimensional radiation position detector achieving both low cost and high resolution can thus be provided.