1. A personal identification device comprising: an image pickup unit; a guide unit to set a finger to be captured; a light source which emits light adapted to be transmitted through the finger and incident on said image pickup unit; an image operating unit which generates a vein pattern from an image picked by said image pickup unit for personal identification, wherein the image operating unit is adapted to detect a contour of the set finger comprising at least two contour lines, calculate a width of the contour, and normalize the image based on a magnification determined by using the width of the contour wherein the normalization is carried out by elastically enlarging or reducing the contour width to a specified value and correcting the two contour lines to parallel straight lines.