1. A personal authentication device, comprising: an imaging section for imaging an eye of a user to capture an eye image including the iris thereof; an iris image creating section for creating an iris image by extracting an image within a region of the iris from the captured eye image; an iris code generating section for generating an iris code by calculating a characteristic value of the created iris image; a determining section for comparing the created iris code with a registered iris code stored in advance in a storage section and determining whether the iris code matches or does not match the registered iris code; a control section for giving an instruction to the imaging section to retry imaging when the determining section determines that the determining section determines that there is no match; a correction angle calculation section, responsive to a determination of no match by the determining section, and to receipt of another iris code generated by the iris-code generating section from another iris image created by the iris image creating section from another eye image captured by the imaging section during a retry imaging instructed by the control section, for comparing the another iris code with the iris code generated from the previously captured image, detecting a shift amount representing a position at which a maximum proportion of the iris code generated from the previously captured image and the another iris code match, and calculating a correction angle for the another iris image corresponding to the detected shift amount; an image angle correction section for correcting an angle of the another iris image based on the calculated correction angle; an average calculation image creating section for computing average values for respective pixels of the two iris images after the angle correction and creating an average calculation image; and an iris code generation instruction section for instructing the iris code generating section to generate an iris code from the created average calculation image.