The present invention relates to an iris recognition device and method capable of improving iris recognition accuracy. To enhance iris recognition accuracy in consideration of variation in pupil size and iris region due to changes in intensity of lighting, the iris recognition device and method are configured to obtain multiple iris images having different iris sizes by capturing iris images of a person to be enrolled with a camera while adjusting brightness of lighting so that the iris size of the person to be enrolled varies from a maximum size to a minimum size, store the obtained iris images and associated iris size information for enrollment in a database interworking with the iris recognition device, and select enrolled iris images having an iris size most similar to that of an iris image captured by the camera for identification among many enrolled iris images for similarity measurement.