1. A biometric authentication apparatus comprising: a comparator that performs authentication of a user by comparing biological information over searchable areas comprising searchable positions read from the user's hand with registered biological information registered in a storage in advance; a high accuracy comparator that compares the biological information with the registered biological information with a higher accuracy instead of comparison using the comparator when the user is not authenticated by the comparator; and a comparison result storage that records a comparison result obtained by the high accuracy comparator in the storage, wherein the comparator generates and records an error authentication data in the storage, when the user is not authenticated by the comparator; the error authentication data comprising a search area indicating an area searched by the comparator and a search position of the biological information at which the degree of similarity becomes largest; the high accuracy comparator compares the biological information and the registered biological information by performing a wide area comparison of an increased search area beyond the search area of the comparator based on the error authentication data, and the high accuracy comparator records in the storage a moved position of the search position at which a degree of similarity in the wide area comparison is largest, the moved position being moved with respect to a reference position of the biological information corresponding to the user, and the comparator determines whether an average of a plurality of moved positions corresponding to the registered biological information of the user stored in the storage over a plurality of authentication occurrences is at least equal to a predetermined value and a standard deviation of the plurality of moved positions is less than a predetermined value, the comparator causes a display of the biometric authentication apparatus to output information to instruct the user to move the user's hand to an opposite direction opposite to a direction of movement of the plurality of moved positions.