1. An apparatus for recognizing a traffic sign, comprising: an image obtaining unit configured to obtain an image from a vehicle at a predetermined range; a region of interest designating unit configured to recognize a traffic sign within the image, and designate an area including the traffic sign as a region of interest; a valid area extracting unit configured to extract a valid area excluding an area of a first color from the region of interest, and calculate valid area data; and a similarity calculating unit configured to calculate similarity between the traffic signs recognized from respective images by using the valid area data.