[Problem] To provide a radiation detector, which can perform high count rate radiation detection and energy information collection at the same time, and which can accurately acquire energy information. [Solution] This radiation detector is provided with: a scintillator, which generates light due to energy applied from radiation inputted thereto； and a plurality of light detectors, which detect, at positions at different distances from the input end of the radiation in the scintillator, the light generated by means of the scintillator. The radiation detector is characterized in that at least some values of d×Zeff 4 (wherein d represents a density (g/cm3) of the scintillator, and Zeff 4 represents effective atomic numbers of the scintillator) are 30×106 or less.
