An image processing apparatus includes a histogram creation unit that creates a histogram from an input image, a detection unit that detects a gradation level of interest from the histogram, a gradation correction parameter generation unit that generates a gradation correction parameter to improve a gradation characteristic in a gradation range around the gradation level of interest, and a correction unit that corrects the gradation of the image using the gradation correction parameter. The detection unit detects, as the gradation level of interest, a gradation level whose frequency is a peak value equal to or more than a predetermined threshold, and which has variation width of frequencies in a predetermined range including this gradation level to be smaller than a predetermined width in the histogram.