An image processing apparatus, which reduces occurrence of color-unevenness and a color shift under low illuminance and high illuminance, includes a data processing means for obtaining image data, converts the image data into frequency data in a frequency band, and performs certain processing on the frequency data, an illuminance detection means for detecting illuminance of the obtained image data, and a changing means for changing the predetermined data processing on certain frequency data in accordance with a result of the illuminance detection.