PURPOSE: To hardly generate perceivable time delay by providing a frame buffer for storing many view points of a displayed model, taking out display information from the frame butter and displaying it.

CONSTITUTION: Resepctive points (supplied by an azimuth and an inclination) of a virtual view field 40 and addressible memory locations inside the frame butter 42 are in correspondence relation and the picture element information of the corresponding respective points of the virtual view field 40 are stored in the memory locations. For the respective samples of the azimuth and the inclination, a computer decides an observing point 32 and a view port 34. Further, the picture element information provided in the view port 34 is taken out and displayed at a head mounted display as the view window 36 of the virtual view field 40. When a user moves a head and moves the line of sight inside the virtual view field 40, an access position in the frame butter 42 is immediately moved. As a result, the view window 36 is continuously updated and images look natural.