A maximum and minimum color information detector detects a maximum color-signal gradation level or a value equivalent to the maximum gradation level and a minimum color-signal gradation level or a value equivalent to the minimum gradation level as color information for an image signal input to the image processing apparatus, a correction parameter generator sets correction parameters according to the color information about the input image signal, and a gradation corrector corrects the gradation scale of each color component of the input image signal according to the correction parameters. Contrast can thereby be improved without excessive color collapse.