Individual authentication method and apparatus therefor, wherein at least one information out of an eyeground blood vessel image information obtained by an optical means, eyeground blood flow distribution image information obtained by using a laser, and information relating to the change over time thereof is compared and collated with personal information registered in advance, and at least the one information out of the eyeground blood vessel image information, the eyeground blood flow distribution image information, and the information relating to the change over time thereof within a measurement field of view obtained in a direction of a line of sight fixed by a fixation target registered in advance is compared and collated with the personal information registered in advance. The fixation target for fixing the direction of the line of sight may be selected from a plurality of fixation points, such as a part of a character string, a part of a still image, or a part of a moving picture, and has an information of which of them to fixedly view registered in advance. An improved technology for further reinforcing the individual authentication method using measurement of an eyeground blood vessel pattern or an eyeground blood flow distribution is provided.