When a predetermined condition based on an instruction input from a user or a change in a posture of the user is satisfied (N in S300), an original image manipulating section of an image generating apparatus acquires amounts of displacement of viewpoints of a viewer from base points with respect to an image stereoscopically viewed by the user on the basis of display of left and right parallax images (S302). On the basis of the amounts of displacement, the original image manipulating section acquires the amount of adjustment of the position of an image plane in a virtual space in which the parallax images are expressed (S304). In generating, from each pixel on the image plane, an image reference vector for referencing the original images of the parallax images, the original image manipulating section executes calculation reflecting the amount of adjustment of the position of the image plane to achieve adjustment of the position of the image plane (S306).