In this method, such as seen from FIG. 21, an uneven surface data detection apparatus uses a prism 2, a finger surface (uneven surface) pattern of a finger 1 having projections (ridges) 6 and recesses (grooves) 5 is pressed against an oblique side portion of the prism 2, and light from a light source 3 is made incident on an oblique side portion thereof at a critical angle or larger.