An iris recognition system includes an eye image input unit calculating the distance between an image obtaining apparatus and a user using a distance sensor. An eye image pretreatment unit calculates a fuzzy entropy for the multifocus eye image sequence input. A feature vector extraction unit multi-divides the multifocus iris image sequence extracted in the eye image pretreatment unit. A recognition unit discriminates the user's authenticity by measuring a dissimilarity between the feature vector extracted from the feature vector extraction unit and a feature vector already registered. A register unit registers the reduced wavelet feature vector extracted from the feature vector extraction unit and the dimension-reducing transform function P in a storage unit. A storage unit stores the dimension-reducing transform function P and the reduced wavelet feature vector.