An image detector comprises: an active matrix-type TFT array substrate having a pixel area, in which photoelectric conversion elements and thin film transistors are arranged in a matrix shape, a data line, and a bias line; a conversion layer, which is arranged on the TFT array substrate and converts radiation into light; and a conductive cover, which covers the conversion layer, wherein the conductive cover is adhered in an adhesion area in an upper layer than an area, in which at least one of the data line and the bias line extend from the pixel area to each of terminals, and wherein inorganic insulation films configured by at least two layers are formed between the at least one of the data line and the bias line and the adhesion area.