In a radiation image detector including a voltage-applied electrode, to which a voltage is applied, and a semiconductor layer for generating charges by irradiation with radiation, which are superposed one on the other, a charge injection prevention layer that covers at least the edge of the voltage-applied electrode is provided. Further, a protruding electrode is provided on the upper surface of the charge injection prevention layer in such a manner that the side surface of an edge of the protruding electrode is located on the outer side of the side surface of the edge of the voltage-applied electrode and the side surface of the other edge of the protruding electrode is located at the position of the side surface of the edge of the voltage-applied electrode or on the inner side thereof.