To provide an image detector in which false images generated by the non-uniform irradiation of reflected light on a sensor substrate and external light within a sensor surface are reduced.

In the image detector for which a sensor layer composed of a plurality of pixels including at least a photoelectric conversion part for photoelectrically converting incident light is formed on a light transmissive insulating substrate, (1) a light diffusing means is provided on at least one of the front surface and back surface of the light transmissive insulating substrate, (2) the light diffusing means is provided on the front surface of the light transmissive insulating substrate viewing from the side of the sensor layer, (3) the light diffusing means is a light transmissive insulating substrate surface made into a rough surface, (4) the light diffusing means is a light diffusing layer, and (5) the light diffusing layer includes a titanium oxide or aluminum.