An image processing device is provided that corrects image data obtained by sequentially reading out as a current, charges from unit regions from a radiographic image detector provided with signal lines extending along a predetermined direction. The correction includes estimating the respective leakage current superimposed on the read-out current when the charge is read out from a target unit region using a leakage current estimation equation, formed from a single exponential function or from a sum of plural exponential functions, for respective leakage currents of unit regions that are positioned along the same signal line as that of the target unit region and whose charges are in an unread state when the charge is being read out from the target unit region, and correcting the image data corresponding to the target unit region on the basis of the leakage current estimate result.