1. A projection-type three-dimensional image display apparatus comprising: projection means for projecting a plurality of element images containing parallax information to a two-dimensional plane; a screen of which light transmittance can be electrically controlled and on which a projection image including the plurality of element images projected by the projection means is formed; and image forming means for forming a three-dimensional image having a vertical parallax and a horizontal parallax in a space in front of the screen from the projection image.