1. An apparatus for detecting a specific feature point from an image including a target object comprising: an image input unit that inputs an image of the target object; a three-dimensional shape information storing unit that stores three-dimensional shape information of a model and three-dimensional position information of reference points in the model, the reference points each differing from the specific feature point; a correspondent reference point input unit that inputs position information of correspondent reference points of the reference feature points on the input image; a correspondent feature point acquiring unit that acquires position information of correspondent feature point of the specific feature point in the model; a correspondence relation acquiring unit that acquires a correspondence relation between the input image and the three-dimensional shape information using the position information of the correspondent reference points and the three-dimensional position information of the reference points; a seek area setting unit that sets a seek area for the specific feature point on the input image by projecting a correspondent area containing the correspondent feature point on surface of the model to the input image based on the correspondence relation; an image information acquiring unit that acquires image information of the seek area from the input image; and a feature point detecting unit that detects the position of the specific feature point in the input image from the image information.