There is provided a finger-vein authentication apparatus including a light source for illuminating one surface of both side-surfaces of a fingertip of a finger with light, and an image sensor for imaging the other surface of the fingertip, the light source and the image sensor being positioned at both sides of a nail of the fingertip with the nail sandwiched therebetween, wherein a fingertip guidance jig for supporting the fingertip and a finger-root guidance jig for supporting a finger-root of the finger are disposed between the light source and the image sensor, a light-shielding unit being disposed on the light-source side, the light-shielding unit being used for shielding the illumination light such that the illumination light will not travel to a ball side of the finger.