A position measurement apparatus comprising: - a camera that is adapted to capture a target object having a reflective surface to obtain a captured image including at least a part of the reflective surface ; - a first storage unit that is adapted to store capturing conditions including a viewpoint position and a shooting direction of the camera ; - a second storage unit that is adapted to store model data including a shape of the target object ; - a marker object that has a plurality of feature points and is fixed at a predetermined position with respect to the camera , the plurality of feature points being fixed at predetermined positions with respect to the marker object; - a third storage unit that is adapted to store feature point data representing a mutual positional relationship among the viewpoint position and the feature points; - a feature-point extracting unit that is adapted to extract multiple feature points of the plurality of feature points from the captured image that is obtained by the camera and in which the multiple feature points are reflected in the reflective surface , and to determine positions of the feature points within the captured image; and - a position measuring unit that is adapted to calculate a position of the target object by iterative calculation starting from an initial value associated with the position of the target object , based on the capturing conditions stored in the first storage unit, the model data stored in the second storage unit, the feature point data stored in the third storage unit, and the positions of the feature points within the captured image determined by the feature-point extracting unit . - a camera that is adapted to capture a target object having a reflective surface to obtain a captured image including at least a part of the reflective surface ; - a first storage unit that is adapted to store capturing conditions including a viewpoint position and a shooting direction of the camera ; - a second storage unit that is adapted to store model data including a shape of the target object ; - a marker object that has a plurality of feature points and is fixed at a predetermined position with respect to the camera , the plurality of feature points being fixed at predetermined positions with respect to the marker object; - a third storage unit that is adapted to store feature point data representing a mutual positional relationship among the viewpoint position and the feature points; - a feature-point extracting unit that is adapted to extract multiple feature points of the plurality of feature points from the captured image that is obtained by the camera and in which the multiple feature points are reflected in the reflective surface , and to determine positions of the feature points within the captured image; and - a position measuring unit that is adapted to calculate a position of the target object by iterative calculation starting from an initial value associated with the position of the target object , based on the capturing conditions stored in the first storage unit, the model data stored in the second storage unit, the feature point data stored in the third storage unit, and the positions of the feature points within the captured image determined by the feature-point extracting unit . <EOS>