1. A stereoscopic display device, comprising: parallax adjustment circuitry configured to receive a left-eye image and a right-eye image and perform a parallax adjustment on the left-eye image and the right-eye image, each one of the left-eye image and the right-eye image including a first region and a second region, the first region being an On-Screen Display (OSD) image region; and display circuitry configured to display an adjusted left-eye image and an adjusted right-eye image which are resultant of the parallax adjustment by the parallax adjustment circuitry, wherein the parallax adjustment circuitry is configured to: perform the parallax adjustment by, in each one of the left-eye image and the right-eye image, shifting only the second region of a respective one of the left-eye image and the right-eye image, and extending the first region of the respective one of the left-eye image and the right-eye image when a section of the second region of the respective one of the left-eye image and the right-eye image adjacent to the first region is lost after performing the shifting.