A head detecting apparatus, including a foreground extraction section for extracting a foreground region in which a person is captured from an input image; a first main axis computing section which includes a first moment computing section for computing a moment around a center of gravity of the foreground region and calculating a main axis of the foreground region based on the moment around the center of gravity of the foreground region; a head computing section for computing a head region included in the foreground region as a part thereof based on the main axis of the foreground region and a shape of the foreground region; and an ellipse determining section for determining an ellipse to be applied to a person's head based on a shape of the head region.