1. A biometric authentication device comprising: an input unit to input identifying information of a user; an image capturing unit to capture an image of a user's hand a plural number of times; a matching unit to extract vein information, on a per image basis, of the hand image captured by the image capturing unit and execute a matching process of matching the vein information with previously-provided vein data associated with the identifying information; a determination data generation unit to acquire determination data specifying based on the hand image whether the hand image is acquired by capturing the living organism or not; and a determination unit to authenticate the user if a matching result of the matching unit on the per hand-image basis demonstrates its normality and if the determination data demonstrates that the hand image is acquired by capturing the living organism, and to authenticate none of the user whereas if not.