Provided is a video system equipped with a video display apparatus and video viewing glasses used for viewing a video displayed on the video display apparatus. The video display apparatus includes: a display section for displaying the video; a synchronizing signal generator for generating an external synchronizing signal in synchronism with the video to notify a display end of a frame constituting the video in synchronism with the video; and a synchronizing signal transmitter for transmitting the external synchronizing signal to the video viewing glasses. The video viewing glasses include: a synchronizing signal receiver for receiving the external synchronizing signal; an optical filter section having a pair of optical filters for adjusting light amounts to be transmitted to left and right eyes of a viewer, respectively; and an optical filter controller for controlling the optical filter section in response to the external synchronizing signal.