1. An object determining device comprising: a detecting part for detecting a face of a person from an input image; a determining part for determining, when a plurality of faces of people are detected by the detecting part, a face to be focused and/or subject on which to perform exposure control when performing imaging from the plurality of faces of people based on positions of the plurality of faces of people; a center determining portion for determining a center of the positions of the plurality of faces of people based on the positions of the plurality of faces of people; and a face determining portion for determining a target face based on the position of the center.