A histogram generating device is disclosed. An embodiment has a brightness signal generating module generating a brightness signal by use of RGB component data of an input frame, an image component data selecting module outputting a single component frame consisting of image component data, which is one of the RGB component data and the brightness signal, an interval histogram generating module generating a level value by calculating the number of image component data belonging to each level grouped by a histogram resolution as a detection interval of the plurality of successive single component frames is changed, and a memory storing a plurality of level values generated for each of the single component frames.