1. A face-image registration device that extracts, from a moving image which is inputted thereto, a face image showing a face of a person and registers the face image in a dictionary, the face-image registration device comprising: representative-face-image extracting means for extracting, from the moving image, at least one face image which satisfies a predetermined representative condition, so as to obtain a representative face image; registration-face-image extracting means for extracting, from the moving image, at least one face image which shows the person shown in the representative face image but is not the representative face image and which satisfies a predetermined registration condition, so as to obtain a registration face image; and face-image registration means for registering, in the dictionary, the registration face image in association with the representative face image.