Generation of residual images due to charge leakage is suppressed. A radiation image detector is constituted by: an upper planar electrode that transmits electromagnetic waves bearing radiation image information; a charge generating layer that generates electric charges when irradiated by the electromagnetic waves which are transmitted through the upper planar electrode; and a plurality of divided electrodes for collecting the electric charges generated by the charge generating layer. The divided electrodes have inclined electrode surfaces, which are inclined with respect to the upper planar electrode.