To identify an individual with uttering sound by using a simple means.

A recording is conducted for an individual who utters alphabets, the Japanese syllabary, numerals, musical scale melody (do, re, mi, fa, sol, la, si, and do), reading aloud and/or intrinsic information of the individual such as his/her name, date of birth, legal domiciles, present address, place of work and names of the family member, and inverse uttering sound recorded by inverting the phase of the above sound. Then, an uttering sound is requested to the individual via synthetic sound and a character display so that the individual utters the recorded items in a random combination. A combination of inverse voice corresponding to the combination of the requested speech is generated to neutralize the uttered speech to obtain 'white color$ bresulting in correct identification of the individual. Note that no cumbersome analysis such as sound spectrogram analysis is required to identify the individual.