1. A stereoscopic image display apparatus comprising: a first object image portion detection hardware processing unit configured to find a desired object image portion from a left-eye image and from a right-eye image constituting a stereoscopic image; a parallax shifting hardware processing unit configured to shift said left-eye image and said right-eye image in such a manner that visual disparity between the object image portion of said left-eye image and the object image portion of said right-eye image, which have been found in said first object image portion detection hardware processing unit, is removed; a display area decision hardware processing unit configured to decide a display area extraction amount from the left-eye image and the right-eye image, the extraction amount containing the desired object image portion the visual disparity of which has been removed by said parallax shifting hardware processing unit, in said left-eye image and in said right-eye image that have been shifted by said parallax shifting hardware processing unit; a display control hardware processing unit configured to control a display unit so as to enlarge and display the image within the display area, which has been decided by said display area decision hardware processing unit, in said left-eye image and in said right-eye image that have been shifted by said parallax shifting hardware processing device; a first determination hardware processing unit configured to determine whether a forward subject image representing a subject present in front of the desired object represented by the desired object image portion detected by said first object image portion detection hardware processing unit is contained in said left-eye image and in said right-eye image; and a second determination hardware processing unit, responsive to a determination made by said first determination hardware processing unit that the forward subject image is contained in said left-eye image and in said right-eye image, said second determination hardware processing unit configured to determine whether amount of disparity between the forward subject image contained in said left-eye image and the forward subject image contained in said right-eye image is outside an allowable range; wherein said display area decision hardware processing unit decides said display area extraction amount from the left-eye image and the right-eye image in accordance with a determination made by said second determination hardware processing unit that the amount of disparity of the forward object is outside the allowable range; and a monitor to display the extracted amount from the right-eye and left-eye image as a result of the display area decision hardware processing unit, said extracted amount including the desired object portion and minimizing a displayed amount of the forward object with disparity outside the allowable range.