A two-dimensional image detector is provided with an active-matrix substrate, which has lattice-shaped wiring, a plurality of thin-film transistors installed at the respective lattice points of the electrode wiring and a plurality of pixel electrodes, an opposing substrate, which has a semiconductor layer having a photoconductive property, and conductive members for connecting the pixel electrodes and the semiconductor electrode. In the gap between the active-matrix substrate and the opposing substrate, areas having no conductive members are filled with an inactive gas.