A multielement radiation detector in which many elements are arranged in array. Each element includes a scintillator which is tilted with respect to the incident direction of radiant rays, and a silicon photodiode which is opposed to the plane of incidence of the scintillator. The light-receiving plane of the silicon photodiode is tilted to meet the inclination of the scintillator. Therefore, the gradient of detection sensitivity distribution is reduced in the thickness direction of the detectors.
