The present invention relates to a new microorganism Weissella cibaria BLS13, and more specifically, to a Kimchi-derived new microorganism Weissella cibaria BLS13 which activates an inhibitory effect on avian influenza viruses, and to uses thereof. According to the present invention, the Weissella cibaria BLS13 or a culture medium thereof contains a substance having an anti-viral function, and thus can be used advantageously in feed additives, fermentation products, foods and medicine.