The purpose of the present invention is to provide a novel composition for improving an oral cavity environment. According to the present invention, a composition for improving an oral cavity environment, which composition contains a fermentation product of propionic acid bacterium as an active ingredient, is provided. This composition can be provided as a food composition. The propionic acid bacterium is preferably Propionibacteriumfreudenreichii, and the fermentation product is preferably a fermented whey product.