The imaging apparatus for authenticating a user can quickly perform matching step of the inputted biometric data. This apparatus for authenticating the user includes an imaging unit for imaging a guided finger and a guided palm, a matching data storing unit for storing the determined finger image and the determined palm image, and a matching unit for matching the imaged finger image and the imaged palm image with the stored finger image and the stored palm image. The matching unit selects the finger image having the similar feature amount based on the imaged finger image and authenticates a user based on the result of matching of the palm image corresponding to the selected finger image with the imaged palm image.