A cannula device having a base body made of plastic, on which a cannula is held, and having a guard element that can be moved relative to the base body into a second position, in which the cannula tip is exposed for the use of the cannula device, from a first position, in which, in the delivered state of the cannula device, the cannula tip is covered to protect the user from injury. The guard element is movable, after use of the cannula device, back into a third position in which the cannula tip is covered to protect a user from injury, and the guard element is irreversibly locked to the base body by a third fixing device including a first latching protrusion protruding from the base body and at least one first latching receptacle, associated with the first latching protrusion in at least one side wall of the guard element.
