A display device includes a display portion for displaying a video, a generator for generating a synchronization signal including a command signal synchronized with display of frame images of the video and a transmitter for transmitting the synchronization signal. The command signal including a predetermined member of pulse signals has a leading pulse signal for notifying a start of the command signal, a terminal pulse signal for notifying an end of the command signal and a control pulse signal for notifying a content of synchronization control synchronized with the display of the frame images.