A Head-Up Display(HUD) is required that can give information to the driver in an easy to understand manner which can prevent traffic accidents. “AR-HUD”s are used to display driving information that overlay the image on the actual scenery. It is important for “AR-HUD”s to see the information and the actual scene at the same time and the depth feeling and the distance feeling are key factors. Binocular parallax used in stereoscopic 3D display is one of the most useful method to provide the depth feeling and the distance. In general, the stereoscopic 3D display sets the image range in the Panum’s fusional area to avoid inhibition of fusion. However, in the case of using the stereoscopic 3D display for “AR-HUD”, the image range must be set beyond the Panum’s fusional area to see the information and the actual scene at the same time. In this study, we were investigated the visibility of stereoscopic 3D display beyond the Panum’s fusional area for “AR-HUD”s. Easiness of fusion was measured by the recognition time when participants watched remote projector images and parallax images beyond Parum’s fusional area at the same time. We found that there was a group that could not recognize the relationship between two images under certain conditions.