A biometrics sensor includes a portion for sucking air, a molecular sieve portion for selectively passing or adsorbing specific gas contained in the air, a gas detecting section for detecting the concentration of gas passed through the molecular sieve or the remaining gas, and a data processing section for comparing the detection result with a prestored detection result, wherein the gas detecting section selectively detects predetermined gas, and the data processing section performs determination or probabilistic determination on an authentication object person by comparing the composition ratio of gas for each authentication object person with a prestored composition ratio.
