There is disclosed an image processing apparatus which applies an adjusting process to an image that includes a pixel to be processed. The image processing apparatus extracts an image area with a predetermined size including the pixel to be processed. The apparatus calculates a variation associated with the pixel to be processed from signal values of pixels included in the image area. The apparatus calculates a variation time count in the image area from the signal values of the pixels included in the image area. The apparatus calculates adjusting levels Fz1, Fz2, and Fe from the variation time count and the variation using a definition unit which defines correspondence among the variation time count, the variation, and the adjusting levels, and applies an adjusting process to a signal value of the pixel to be processed by the calculated adjusting levels. Note that the definition unit defines the correspondence so that the adjusting levels Fz1, Fz2, and Fe progressively change in accordance with different variation time counts or different variations.