VIDEO DISPLAY SYSTEM

A video display system for suppressing variations of a video image display position and improving viewing comfort includes: a projector (1100) which projects a video projection light; and a screen unit (1150) which receives the video projection light and displays the video image. The screen unit (1150) includes first and second light detection units (1161 and 1162) which detect the received video projection light. The projector (1100) includes a control unit (1205) and an adjustment unit (106) which derive displacement in the display position of the video image based on the light detection results of the first and second light detection units (1161 and 1162) and control the output mode of the video projection light so as to suppress the displacement.