An image pickup device includes a histogram generation unit which generates a histogram representing a brightness distribution of digital image data (RAW data) acquired during picture taking and a table change unit which calculates an amount of correction with reference to a target brightness value based on the histogram and changes gradation correction information of a gamma lookup table in accordance with the amount of correction. A gamma correction unit corrects gradation of the image data using the changed gradation correction information to generate a taken image whose brightness is corrected in accordance with the target brightness value.