To provide a mosquito noise removing method for reducing a mosquito noise, and for storing an edge part.

When executing horizontal filtering in each horizontal line, if there are pixels other than central pixels included in the horizontal lines whose pixel values have a difference with the pixel values of the central pixels, whose absolute values are not less than a first threshold, the pixel values of those pixels are replaced by the pixel values of the central pixels, and then filtered. When executing vertical filtering by using correction values for the central pixels of each horizontal line to a vertical line consisting of the central pixels of each horizontal line, if there are pixels other than the central pixels included in the vertical line whose correction values have any difference with the correction values of the central pixels, whose absolute values are not less than a second threshold, the correction values for those pixels are replaced with correction values for the central pixels, and then filtered.