Problem to be solved. To provide a low-cost beverage filling system without impairing functions such as cleaning in place. Solution. The beverage filling system comprises: a sterilization section for sterilizing a product liquid; a storage section for temporarily storing the product liquid supplied from the sterilization section; and a filling section for filling the product liquid supplied from the storage section into a container. A cleaning/sterilization mechanism for cleaning and sterilizing, provided in at least either the sterilization section or the filling section, carries out cleaning in place and sterilization in place of a mechanical component of the filling section.