1. A position and orientation measurement method comprising: a first image input step of inputting a first image captured by a first image capture device which captures an image of a physical space; a second image input step of inputting a second image captured by a second image capture device which has a fixed position and orientation relative to the first image capture device and has a spatial resolution different from the first image capture device; a first detection step of detecting, from the first image, a feature amount associated with image coordinates of an index on the physical space; a second detection step of detecting, from the second image, a feature amount associated with image coordinates of an index on the physical space; and a position and orientation calculation step of calculating a position and orientation of the first image capture device based on the feature amounts associated with the image coordinates of the index detected in the first detection step and the second detection step.