An image processing apparatus includes: a difference calculation unit that calculates a difference value of a feature amount of image data of a predetermined region between a present frame and a past frame; a first counting unit that counts number of times when an absolute value of the difference value exceeds a threshold during a predetermined period of time; a second counting unit that counts number of times when the difference value of the image data have different plus-minus signs between a present frame and a past frame during a predetermined period of time; and an identification unit that identifies a light source frequency by comparing the output of the second counting unit with a predetermined value when the output of the first counting unit exceeds a predetermined value.