When a 2-dimensional video image is displayed, a front/rear feeling and a stereoscopic feeling are enabled to be expressed. A detection signal Sd is formed by a high pass filter 25 and a rectifying circuit 26 in accordance with an amount of edge information. The detection signal Sd is supplied to a variable delay circuit 14L. A detection signal Sd′ is supplied to a variable delay circuit 14R. The variable delay circuits 14L and 14R are controlled in accordance with the edge information amount so that a video image for the left eye and a video image for the right eye are moved in the opposite directions. Thus, an imaginary image is synthesized to the front or rear side from a display plane. The left and right video images are displayed on CRTs 20L and 20R. The projection light passes through a horizontal polarizing filter 21L and a vertical polarizing filter 21R and the left and right video images are overlapped on a screen 22. The left and right video images are separately observed by glasses 23 having polarizing filters 24L and 24R and a stereoscopic feeling is enhanced.