The tracking target subject specifying unit specifies a tracking target subject in image data. The first tracking position detection unit detects first characteristic information from the image data and set a first candidate tracking position based on the first characteristic information. The second tracking position detection unit detects second characteristic information from the image data and detect a second candidate tracking position based on the second characteristic information. The reference information acquisition unit acquires reference information. The control unit decides a true tracking position based on two determinations.