Abstract: The invention refers to a syringe of single-use type intended for injection or lab tests with an injection needle slidable into the syringe after usage. The intention with this is to eliminate the risk for prick injuries when the syringe is handled after usage. A design of a single-use syringe such that the needle becomes kept in the interior of the syringe after usage has proved to be involved by different kinds of complications and has made the syringe complicated and expensive to manufacture. An uncomplicated and reliable syringe of the kind stated in the introduction is achieved according to the invention by the fact that the plunger (2) of the syringe is provided with a coupling device (12) designed such that in the completely pushed in position of the plunger the rear part of the injection needle (6) is coupled to the plunger (2) and follows the plunger when the plunger is withdrawn.