A sampling device including a closed sample container with a flexible wall and with an interior, a coupling member for releasable coupling to a sample outlet connector, a communicating passage between the coupling member and the interior of the sample container, at least the interior of the sample container being sterile, and a sterility protection device for ensuring the sterility of the interior of the sample container in the form of a three-way valve between the coupling member and the sample container, the three-way valve having a connection to the coupling member, a connection to the sample container and an outlet, and the three-way valve being, before use, in a closed position in which it bars access to the interior of the sample container.