A digital X-ray detector comprises a pixel array including a plurality of pixel regions； and a data line； and a read-out driver connected to the data line, wherein each pixel region includes a photo-sensing element and a pixel switch disposed between the photo-sensing element and the data line, wherein the read-out driver includes: an amplification unit connected to each data line； a first association signal detector connected to an output of the amplification unit and detecting a first association signal corresponding to an offset of the amplification unit； a second association signal detector connected to the output of the amplification unit and detecting a second association signal including an output signal of the photo-sensing element； and a third association signal detector connected to the output of the amplification unit and detecting a third association signal corresponding to an offset of the pixel region.
