To make it possible to stably provide a stereoscopic image which can be viewed by each viewer in the state where the stereoscopic effect and the sense of reality are maximized. 
Left eye and right eye images (images for measurement), the 
parallax between which is continuously or stepwise changed, are outputted beforehand to a stereoscopic 
image display device, and the face of the viewer viewing the images for measurement is photographed. The 
pupil width of the photographed viewer is measured, and based on the state of the change in the 
pupil width, the fusion limit of the viewer is measured and registered. In the case where a stereoscopic image for appreciation is displayed, the stereoscopic image is outputted by controlling the 
parallax of the stereoscopic image so as to prevent the 
parallax from exceeding the fusion limit of the viewer, which is measured beforehand.