Optical tracking system includes a marker portion, the upper and results processing. A marker portion arranged at a distance from the pattern and the pattern having a specific information and a first lens having a first focal length. Image forming portion disposed away from the second lens and a second lens having a second focal length, and includes an imaging unit that is the image of a pattern imaged by the first lens and the second lens. Processing unit tracking section determines the marker portion from the position coordinate conversion equation between the pixel coordinates on the image of the coordinates and the pattern on the pattern surface of the pattern and the marker using the marker portion as determined posture. This makes it possible to correct the tracking section marker in a more simple and easy way