PURPOSE: To offer the gamma correcting device and the gamma correcting method by which an ideal characteristic can be obtained.

CONSTITUTION: A video signal outputted from a CCD 12 is subjected to gamma correction by an analog gamma correcting circuit 15 to which a first gamma correction value is set, and a dynamic range is narrowed. This video signal is converted to digital image data by an analog/digital converting circuit 17 and given to a look-up table 18. In the look-up table 18, gamma correction data for executing a gamma correction by a second gamma correction value corresponding to a ratio of a desired gamma correction value and the first gamma correction value is stored or set in advance, and the image data is subjected to gamma correction digitally and outputted from the look-up table 18.