1. A structural element detecting apparatus for detecting predetermined structural elements included in predetermined subjects from within images that include the subjects, comprising: a structural element candidate detecting section, for detecting structural element candidates by discriminating characteristics inherent to the predetermined structural elements, from among characteristics of the images; a subject detecting section, for detecting subjects that include the structural element candidates by discriminating characteristics inherent to the predetermined subjects, from among characteristics of the images in the vicinities of the structural elements candidates; and a structural element confirming section, for confirming that the structural element candidates are the predetermined structural elements, by discriminating characteristics inherent to the predetermined structural elements with a higher degree of accuracy than that of the structural element candidate detecting section, from among the characteristics of the images in the vicinities of the structural element candidates, which are included within subjects detected by the subject detecting section.