1. An iris recognition system using a mobile device including a stereo camera, a digital camera chip and a video input unit, the mobile device being operated in cooperation with an iris image registered and stored in other mobile devices, a remote server or a security device, the iris recognition system comprising: the stereo camera including a single-focus lens having a long depth of focus, for taking a picture of the face and iris of a user to acquire a stereo image; a means for converting the stereo image acquired by the stereo camera into a digital signal and calculating the distance between the stereo camera and the iris; a means for determining whether the stereo image is out of focus and whether the position of the iris is out of a photographing range of the stereo camera using the calculated distance and judging whether the stereo image is suitable for personal identification; and a means for extracting an iris region from the stereo image and obtaining an image having a normalized size using polar coordinate conversion and interpolation methods.