A problem to be solved by the present invention is to provide lactic acid bacteria effective for promoting health, particularly for prophylaxis or therapy of oral diseases. The inventors of the present application searched for lactic acid bacteria that are effective for promoting health, particularly for prophylaxis or therapy of oral diseases, and found that a lactic acid bacterium belonging to the genus Weissella, particularly a lactic acid bacterium W3 belonging to the genus Weissella (accession number: NITE BP-01789) is effective for prophylaxis or therapy of oral diseases.