1. An information processing apparatus comprising: an image acquisition unit for acquiring a real-world image; a space analysis unit for analyzing a three-dimensional space structure of the real-world image; a scale reference detection unit for detecting a length, in a three-dimensional space, of an object to be a scale reference that is included in the real-world image; and a scale determination unit for determining, from the length of the object detected by the scale reference detection unit, a scale of the three-dimensional space.