A paper currency sorter comprises a fixing rack, and a paper currency guiding plate is fixed at the lower side of the fixing rack and is equipped with at least one notch. An image scanner is arranged at the lower side of the paper currency guiding plate, and a gap through which a paper currency can pass is arranged between the image scanner and the paper currency guiding plate. A pivotal shaft pivots and is fixed on the fixing rack, and comprises at least one driving wheel. The lower part of the driving wheel penetrates the notch and is accommodated in the gap, and the driving wheel is rotated to drive the paper currency to pass through the gap, thereby preventing the paper currency from being blocked by the image scanner.