1. A position and orientation measurement method, comprising: an input step of inputting sensed images of a plurality of frames time-serially sensed by an image sensing device; a detection step of detecting indices allocated in a physical space from each of the sensed images; an acquisition step of acquiring, with respect to each of the indices detected in the sensed image of a frame of interest, a detection state of an identical index from frames before the frame of interest; and an estimation step of estimating a position and orientation of the image sensing device using at least information associated with image coordinates of the respective indices detected from the frame of interest in the detection step and the detection state of the identical index from the frames before the frame of interest acquired in the acquisition step.