The present invention provides a stereoscopic-image display apparatus and a stereoscopic-image display method, which can improve the comprehensive performance by simple structure. Mediums that are arranged opposite to an elemental-image display unit, that form two lens arrays having different principal planes together with substrates, and that switches a polarization direction of incident light corresponding to applied voltage, thereby making lens effect of either one of the lens arrays effective are included. By controlling the polarization direction synchronizing with a display timing of images to be displayed on the elemental-image display unit, the lens array to be effective is switched at each display timing, and images having different near or far direction are alternately displayed on the elemental-image display unit.