A culture container includes a container and a cover. The container forms an opening at the top and an external threaded portion around the opening. The cover includes a main body and a flange extending from the main body. An internal threaded portion corresponding to the external threaded portion is formed on the internal surface of the flange. The cover forms a ventilation passage having an opening formed at a free end of the flange facing away from the main body. When the internal threaded portion is threaded with the external threaded portion so as to close the opening of the bottle, the interior of the bottle communicates with exterior via the ventilation passage. Thus, dust is prevented from falling into the bottle via the ventilation passage.