A noise-reduction processing device including: a part that calculates an edge strength indicating the edge amount at the pixel of interest based on the pixel of interest and surrounding pixels that surround the pixel of interest; a part that discriminates the edge direction at the pixel of interest; a first filter-processing part that subjects the pixel of interest to smoothing processing along a direction that is based on a direction-discrimination result and outputs a first filter-processing result; a second filter-processing part that subjects the pixel of interest to smoothing processing producing a lower low-pass effect than that of the first filter-processing part and outputs a second filter-processing result and a part that synthesizes the first and second filter-processing results, with the ratio of the first filter-processing result increased as the edge strength becomes higher and the ratio of the second filter-processing result increased as the edge strength becomes lower.