A stereoscopic image display method, in which parallax images for right and left eyes from a parallax image source are divided into a plurality of stripe pixels, a stripe image obtained by arranging the plurality of stripe pixels in a horizontal direction in a predetermined order is displayed on a display, a light beam which comes from the stripe image displayed on said display and has a plane of polarization in a predetermined direction is guided to a polarization optical element constituted by arranged, in the horizontal direction, vertically elongated stripe-shaped polarization plates so that adjacent polarization plates have orthogonal optical axes, via a phase shift member which selectively sets incident light in one of two different phase shift states in accordance with an electrical signal and outputs the light, and the stripe image displayed on said display is observed using the light beam transmitted through said polarization optical element, comprising the steps of:
- changing over left and right image displays of said stripe image;
- and
- changing the polarization state of the light beam transmitted through said phase shift member by controlling the electrical signal to be applied to said phase shift member in synchronism with the step of changing the polarization state;
- wherein when a polarization direction of light from said phase shift member lies in a first state of said different phase shifts, in an area having a first optical axis in said polarization optical element, the light is transmitted, and in an area having a second optical axis in said polarization optical element, the light is not transmitted, and
- wherein when a polarization direction of light from said phase shift member lies in a second state of said different phase shifts, in an area having a first optical axis in said polarization optical element the light is not transmitted, and in an area having a second optical axis in said polarization optical element, the light is transmitted;
- whereby changing-over of parallax barriers by said stripe-shaped polarization plates is performed.