A CT apparatus 120 is a so-called CT scanning apparatus that captures a tomographic image of the whole or a part of the area from the upper jaw to the lower jaw of a patient, and outputs CT data (captured image data). An oral cavity scanner 200 is an apparatus that obtains a stereoscopic image by optically capturing an image of the inside of an oral cavity in a state that a plate 110 is fixed to teeth, and outputs the stereoscopic image as three-dimensional shape data. A processing apparatus 190 computes a positional relationship between the teeth and fiducial frame markers on the basis of the CT data and three-dimensional shape data that are obtained by image-capturing performed in a state that the plate 110 is put on the teeth, and a positional relationship between plate markers and the fiducial frame markers.
