We propose an autostereoscopic display using a parallax barrier with an eye-tracking system to expand the viewing zone in all directions in both portrait and landscape modes. High-quality 3D images can be observed even if the viewer moves from the optimum viewing position. According to the viewing position, we divide a screen into multiple areas and control the optimal binocular image positions of each divided area to expand the viewing zone in the depth direction. The same eye-tracking algorithm can be applied to barriers in the portrait and landscape modes. To verify the effectiveness of the proposed system, we measured the crosstalk ratio of prototypes according to the viewing position.