A vein authentication apparatus is disclosed. The apparatus may include an imaging unit having a plurality of imaging sections. Each imaging section may be configured to image light reflected from a vein plexus inside a finger and light transmitted through the vein plexus. The apparatus may also include an illumination source located on the same side as the imaging unit with respect to the vein plexus and configured to emit near-infrared light. The apparatus may further include a controller. The controller may be configured to perform authentication processing on the basis of an image imaged by the imaging unit and vein information previously stored. The controller may also be configured to control the illumination source such that the near-infrared light emitted from the illumination source is scattered behind a vein section corresponding to an imaging section being in an imaging period among the plurality of imaging sections.