The present invention provides a finger vein authentication unit 101 which solves problems such that a turn of a finger 4 around the finger as an axis cannot be detected from an image of the finger 4, a finger cannot be placed normally because the nail is caught in a dent portion, and an image of the contour of a finger 4 cannot be obtained by an image capturing method using an image pickup window W which is narrower than a finger 4 and is completely closed with a finger so that a turn of a finger cannot be detected from the counter. A touch sensor 5 having an X-Y matrix capable of obtaining the position and shape of a fingertip is mounted in a fingertip placement part, and the fingertip placement part is formed in a flat shape so that a finger is easily put. From the data of the position and shape of the fingertip read by the sensor 5, a turn of the finger around the optical axis of the camera 6 as a center, a turn of the finger around the finger as an axis, and a positional deviation of the finger are detected. On the basis of the data, the vein is extracted accurately and used for a guidance to the user so that the user can put his/her finger in the correct position.
