a synchronizing signal extracting device comprises means for detecting each pulse included in a composite synchronizing signal ; means for generating a first pulse in synchronism with the detected pulse or detected pulse having a predetermined width ; and means including a gate circuit to which the first pulse is supplied , and operative to open the gate circuit after lapse of a predetermined time period from the rise of the detected pulse and extract , as a synchronizing pulse constituting a synchronizing signal to be extracted , the first pulse passed through the gate circuit .