Provision is a radiation detector that allows eliminating short between electric wires crossing over each other via an interlayer insulating layer and thus suppression of defective detecting elements. A construction of this embodiment has a design idea that eliminates short between electric wires of an amorphous selenium layer and an active matrix substrate. Specifically, the electric wires are in a position covered with a thick center portion of the amorphous selenium layer. This ensures to separate the electric wires away from an electrode layer, achieving provision of a radiation detector capable of being used for a long period of time.