The invention relates to a syringe closure for a syringe having a basic body, a terminal extension that extends from the basic body, which has a free end and a base arranged on the basic body. A recess is provided on the extension at a distance from its free end. The syringe closure for closing off the syringe can be attached in such a way on its extension via its free end that the syringe closure overlaps at least one recess of the extension. The syringe closure is characterized by a locking device having at least one locking element, which assumes a release position in a first functional position after the attachment of the syringe closure on the extension, and ensures a positive engagement with at least one recess on the extension in a second functional position, the locking position, and thus lockingly holds the syringe closure on the extension.
