Provided is a video system equipped with a video display apparatus, and video viewing glasses for use in viewing a video displayed on the video display apparatus. The video display apparatus includes: a display section for displaying a video; a synchronizing signal generator for generating an external synchronizing signal for notifying an end of displaying 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 amounts of light to be transmitted to a left eye and a right eye of a viewer, respectively; and an optical filter controller for controlling the optical filter section based on the external synchronizing signal.