1. A personal identification device comprising: a dictionary data storing section that stores identification dictionary data for a person to be identified, which is generated from feature data extracted from an identification element for identifying the person, in association with person-specifying information for specifying the person; identification means for comparing feature data extracted from an identification element extracted from the person, against the identification dictionary data in the dictionary data storing section to identify a person who has the captured identification element; time acquiring means for acquiring information on capture time of an identification element captured from the person; person-specifying means for obtaining the person-specifying information that specifies a person who has the captured identification element, on the basis of a result of identification of the person by the identification means; dictionary-data generating information storing means for adding and storing data of the captured identification element or feature data extracted from the identification element, and time information acquired by the time acquiring means into the dictionary-data generating information storing section, in association with the person-specifying information acquired by the person-specifying means; and dictionary data update processing means for generating or updating the identification dictionary data corresponding to the person-specifying information acquired by the person-specifying means, by using information on capture time newly acquired by the time acquiring means, information on capture time of the identification element acquired previously and stored in the dictionary-data generating information storing section in association with the person-specifying information acquired by the person-specifying means, and feature data captured at each capture time, the dictionary data update processing means being configured to update the identification dictionary data by weighting each piece of the feature data by a weighting factor according to its capture time.