1. A monitoring apparatus comprising: a plurality of image capturers configured to capture a face image of a matching target person; an accumulation unit configured to accumulate the face image of an accumulator in an accumulator database; area storage configured to store an area where the face image is captured with respect to each of the plurality of image capturers; an area specifying unit configured to specify the area where the face image of the matching target person is captured by the image capturers based on information stored in the area storage; a matcher configured to perform matching by calculating a degree of similarity between the face image of the matching target person and the face image of the accumulator stored in the accumulator database; a matching determination unit configured to determine whether the face image of the matching target person is matched with the face image registered in the accumulator database by comparing the degree of similarity, which is of a matching result of the matcher, to a predetermined threshold; area history storage configured to store the area specified by the area specifying unit in an area history database while correlating the area with identification information identifying the face image of the accumulator when the face image of the matching target person is matched with the face image registered in the accumulator database; a provisional registration unit configured to make a provisional registration of a predetermined flag while correlating the predetermined flag with the face image corresponding to the identification information in the accumulator database when a pattern of the area, which is stored in the area history database while correlated with the identification information of the face image, is a predetermined area pattern; and a definitive registration unit configured to make a definitive registration of the predetermined flag while correlating the predetermined flag with the face image of the matching target person in the accumulator database, when the face image of the matching target person is matched with the face image of the accumulator in which the provisional registration of the predetermined flag is made in the accumulator database, and when the face image of the matching target person is captured in a predetermined area.