Provided is an image process apparatus for processing a color image signal, including: an integration unit integrating at least one of each of color signals of the color image signal or a brightness signal obtained from the color image signal over at least one horizontal period; a normalization unit normalizing an integration value obtained by the integration unit and a difference between the integration values of adjacent fields or frames obtained by the integration unit; a frequency analysis unit extracting spectrum of output values of the normalization unit; a flicker component estimating unit estimating a flicker component from the spectrum extracted by the frequency analysis unit; an index generating unit calculating an index representing a degree that a photographing light source is estimated to a fluorescent lamp, based on an estimated result of the flicker component estimating unit; and a color balance control unit calculating a color balance control value of the color image signal according to the index from the index generating unit.