A solid state radiation detector having a sub-striped electrode is provided, which is capable of effectively erasing residual images accumulating in the region adjacent to the outer edge of the first conductive layer. The detector has a planar first conductive layer; a recording photoconductive layer; a charge transport layer; a reading photoconductive layer; a striped electrode composed of multitudes of linear elements; and a sub-striped electrode composed of multitudes of linear elements. The element partly lying in the image detection area is formed to have a greater width in the non-image-detection area than in the image detection area. In addition, the element entirely lying in the region outside of the image detection area is formed to have a greater width than the width in the image detection area of the element partly lying in the image detection area.