PURPOSE: To increase the selection range (degree of freedom) of screens for a viewer by displaying simultaneously plural screens on a single display device and changing the viewing positions of screens.

CONSTITUTION: The number of screens which are simultaneously displayed is designated by a screen number designation key, and the screen light emitting elements 21, 22 and 23 of A, B and C are prepared for each of elements 20 which construct a screen 13. The beams emitted from the elements 21-23 are sent in the directions α°, β° and γ° respectively so that the independent screens are recognized. Thus it is possible to display plural screens on a single display device and to enable a viewer to enjoy his preferable screens by changing the viewing positions.