1. An iris recognition system using a multifocus image sequence comprising: an eye image input unit calculating the distance between an image obtaining apparatus and a user using a distance sensor to receive a multifocus eye image sequence having focus information of the user's eye varied at regular time intervals within a predetermined distance using the image obtaining apparatus; an eye image pretreatment unit calculating a fuzzy entropy for the multifocus eye image sequence input from the eye image input unit to select eye images of N number that can effectively express eye image data of various focusing levels, and extracting a multifocus iris image sequence by separating an iris image between pupil and collarette that has various iris patterns, from which an ar ea unnecessary for configuring a feature vector is removed, from the selected eye images; a feature vector extraction unit multi-dividing the multifocus iris image sequence extracted in the eye image pretreatment unit, forming a wavelet feature vector from the multi-divided images using a subband including only a low-frequency area, and generating a wavelet feature vector reduced to a dimension having a high discrimination performance and a dimension-reducing transform function P; a recognition unit discriminating 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 registering the reduced wavelet feature vector extracted from the feature vector extraction unit and the dimension-reducing transform function P in a storage unit; and a storage unit storing the dimension-reducing transform function P and the reduced wavelet feature vector.