An X-ray detector includes a plurality of photodiodes arranged in a matrix shape and respectively connected to switching devices, a plurality of gate lines formed in a first direction and connected to the switching devices； a plurality of data lines, wherein N data lines are formed in each second-direction column of the matrix shape, wherein N is greater than 1； and a read-out circuit connected to the plurality of data lines and configured to read out photocurrents from the plurality of photodiodes and convert the photocurrents into X-ray image data, wherein each of switching devices included in each second-direction column of the matrix shape is connected to one of the N data lines.
