A visual image system is constructed as including: a three-dimensional visual image reproducer for transmitting a three-dimensional video signal; a parallax quantity detecting section for detecting a parallax quantity in the three-dimensional video signal from the three-dimensional visual image reproducer; a fatigue measure estimating section for estimating the degree of fatigue based on the detected parallax quantity and outputting an image switching signal correspondingly to a fatigue measure estimating quantity; a 3D/2D image switching section for providing an output by switching between three-dimensional and two-dimensional images based on the image switching signal; and an image display section for displaying a three-dimensional image or a two-dimensional image. The visual image system thereby fulfills the capability of suitably controlling the degree of three-dimensionality of stereoscopic images by inferring from the inputted video signal the degree of effects likely to be produced on the observer.