An apparatus includes an evaluation acquisition unit, a chromaticity value calculation unit, a weight coefficient calculation unit, a histogram analysis unit, an appearance at a light source calculation unit, a white balance coefficient calculation unit, and a white balance operating unit. the evaluation acquisition unit acquires color signal values from image data. The chromaticity value calculation unit calculates chromaticity values from the color signal values. The weight coefficient calculation unit extracts a signal value as a lightness value, and calculates a weight coefficient determined by the lightness value. The histogram analysis unit calculates the center position of a histogram, a histogram multiplication value and a histogram dispersion value. The appearance at a light source calculation unit calculates an appearance at a light source for each color temperature. The white balance operating unit executes a white balance operation with respect to the image data using a white balance coefficient.