An image processing apparatus for edge sharpening, comprising: an image converter; a ringing incidence estimation unit; a sharpness estimation unit; an adjustment factor calculator; and an adjuster, wherein the image converter is configured to perform edge sharpening on an input image data to generate converted image data, a plurality of pixels in the input image data (S 1) are subjected to a determination on whether a ringing flag should be set thereon, wherein the ringing incidence estimation unit is configured to set a ringing flag on a target pixel if ringing is expected to occur on the target pixel, on the basis of a characteristic quantity of a near pixel region including the target pixel and multiple pixels adjacent to the target pixel in the input image data, the ringing incidence estimation unit is configured to estimate an incidence of ringing of the target pixel on the basis of the number of pixels on which the ringing flag is set in a near pixel region including the target pixel and a plurality of pixels near the target pixel, the sharpness estimation unit is configured to estimate a sharpness emphasis level, wherein the sharpness emphasis level is an index indicating the level of blurring of the input image data and all pixels included in the input image data have the same sharpness emphasis level, the adjustment factor calculator is configured to calculate an adjustment factor, wherein when the ringing flag is set on the target pixel, the adjustment factor is calculated based on the incidence of ringing and the sharpness emphasis level, otherwise the adjustment factor is calculated based on the sharpness emphasis level, and the adjuster is configured to perform an adjustment process to calculate a gradation value of the target pixel included in output image data by adding the gradation value of the target pixel included in the converted image data multiplied by α and the gradation value of the target pixel included in the input image data multiplied by 1-α, wherein α is the adjustment factor. an image converter; a ringing incidence estimation unit; a sharpness estimation unit; an adjustment factor calculator; and an adjuster, wherein the image converter is configured to perform edge sharpening on an input image data to generate converted image data, a plurality of pixels in the input image data (S 1) are subjected to a determination on whether a ringing flag should be set thereon, wherein the ringing incidence estimation unit is configured to set a ringing flag on a target pixel if ringing is expected to occur on the target pixel, on the basis of a characteristic quantity of a near pixel region including the target pixel and multiple pixels adjacent to the target pixel in the input image data, the ringing incidence estimation unit is configured to estimate an incidence of ringing of the target pixel on the basis of the number of pixels on which the ringing flag is set in a near pixel region including the target pixel and a plurality of pixels near the target pixel, the sharpness estimation unit is configured to estimate a sharpness emphasis level, wherein the sharpness emphasis level is an index indicating the level of blurring of the input image data and all pixels included in the input image data have the same sharpness emphasis level, the adjustment factor calculator is configured to calculate an adjustment factor, wherein when the ringing flag is set on the target pixel, the adjustment factor is calculated based on the incidence of ringing and the sharpness emphasis level, otherwise the adjustment factor is calculated based on the sharpness emphasis level, and the adjuster is configured to perform an adjustment process to calculate a gradation value of the target pixel included in output image data by adding the gradation value of the target pixel included in the converted image data multiplied by α and the gradation value of the target pixel included in the input image data multiplied by 1-α, wherein α is the adjustment factor.