A thin, lightweight, and highly reliable energy ray detector that enables high-speed reading is provided. An energy ray detector (1) includes TFTs (20) that are arranged in a grid pattern and that each have an active layer formed of a semiconductor having an electrical property changing in accordance with the amount of applied energy ray radiation, and a property detection circuit unit (5) and a controller (60) that detect information regarding the energy ray radiation from changes in the electrical property of the TFTs (20).
