A personal authentication method comprising imaging, on an image sensor as a laser speckle using an optical system, light reflected from retinal blood vessels of the ocular fundus and a blood vessel layer in ocular fundus internal tissue when a laser beam is expanded and made to irradiate the ocular fundus, calculating a quantity that represents the rate of change with respect to time of the amount of light received for each pixel of the laser speckle, obtaining an ocular fundus blood flow map as a two-dimensional map of the numerical values of the quantity, and comparison-checking against pre-registered personal data utilizing at least one, observed in the blood flow map, of blood flow distribution data, a pattern reflecting the course of retinal blood vessels, a pattern reflecting the course of blood vessels in ocular fundus internal tissue observed superimposed thereon, and data on changes thereof over time, and a device therefor. In accordance with the method and device of the present invention utilizing the ocular fundus blood flow rate map, a personal authentication method and device can be obtained that have remarkably higher accuracy than conventional methods and devices.
