1. An object identifying device for identifying whether an object whose posture displayed in an image varies, the object identifying device comprising: a plurality of preliminary identifying means that: obtains, from the image, a feature quantity previously set to identify, in the image, an identification target object that is the object predetermined as an identification target; and calculates a score according to the obtained feature quantity and score calculation conditions previously determined to be different from each other, the score representing a reliability that the identification target object is displayed in the image; a score-vector generating means that generates a score vector having the scores calculated by the plurality of preliminary identifying means as elements thereof; a cluster determining means that determines, in previously determined clusters for classifying the score vector, a cluster that includes the score vector generated by the score-vector generating means; and a main identifying means that: has determination conditions previously determined, for the respective clusters, for determining whether the identification target object is displayed in the image; and identifies the identification target object displayed in the image based on one of the determination conditions, the one of the determination conditions corresponding to the cluster determined by the cluster determining means.