The present invention provides a technique for performing gamma correction processing when there are a plurality of characteristic areas, each of which is characterized by the high frequency in a luminance histogram to improve the impression of contrast. According to the present invention, a luminance characteristic detector (4) detects the luminance of an input image signal and a microcomputer (5) calculates an APL and a luminance histogram of an input image signal. A gamma correction circuit (6) performs the gamma correction processing in response to the luminosity of the input image signal by use of the result of the calculation carried out by the microcomputer (5). Then, if there are a plurality of characteristic areas, each of which is characterized by the high frequency in the luminance histogram, a characteristic emphasis circuit (7) performs grayscale extension processing for the plurality of characteristic areas. This makes it possible to perform the most suitable processing in response to the input image signal so that the impression of contrast is improved.