1. An object determining device comprising: a detecting part for detecting a face of a person from an input image; a classifying part for classifying, when a plurality of faces of people are detected by the detecting part, the plurality of detected faces of people into a plurality of clusters; a temporary determining part for determining a face to be focused and/or face on which to perform exposure control when performing imaging from faces of people in the cluster for each of the plurality of clusters; and an ultimate determining part for ultimately determining the target face from the faces determined by the temporary determining part.