1. An iris recognition system, comprising: an image selector for selecting an image in a best state from a plurality of iris images inputted from an image input device; an internal edge extractor for extracting an internal edge of the selected iris image; an external edge extractor for extracting an external edge of the selected iris image; an iris area normalizer for normalizing an iris area; a security level applier for securing the iris which increases according to age; a rotated image processor for processing an inclined iris image; a feature value extractor for extracting a feature value from the iris image; and a consistency decider for comparing the extracted feature value with a stored iris code to decide whether the compared feature value and iris code are consistent, wherein the image selector is operable to scan an inputted iris image in pixel unit by using a mask defined into a second area which is in square shape and a first area configured as the peripheral girth of the second area, calculate a first number of pixels located in the first area for which a luminance value is smaller than a first threshold value and a second number of pixels located in the second area for which a luminance value is greater than a second threshold value, and select an image for which the second number of pixels is minimized.