1. A personal identification apparatus comprising: a light source that radiates light onto a finger of a person to be identified; an imaging unit which captures a transmitted light from the finger irradiated by the light of the light source; and an image processing unit which extracts a vessel pattern of the finger in accordance with an image which has been captured by the imaging unit; wherein an amount of light of the light of the light source is arranged to be controlled in accordance with information on a position within the finger to be irradiated by the light, and the image processing unit extracts the vessel pattern in accordance with the image having been captured with the light whose amount has been controlled.