1. A stereo image matching apparatus comprising at least one processor which includes: a hit distributor distributing values of each pixel of stereo images into sequential N bits and outputting a plurality of stereo images including the sequential N bits; a plurality of cost calculators each receiving the plurality of stereo images and calculating matching cost, values for each pixel of each of the stereo images; a confidence calculator calculating a matching confidence by using cost characteristics of the respective matching cost values calculated by the plurality of cost calculators; and a depth determiner determining that a depth value of which the matching confidence is high and the matching cost values are relatively low is a final depth value.