Abstract: The invention relates to an injection device, in particular for once-only use, for injecting an implant which can release a drug in a controlled manner, which device comprises a housing which is provided at the injection end with an injection needle in which the implant can be disposed and in which a passage opening is disposed at the actuating end of the housing for a plunger, mounted in the housing and displaceable in the axial direction of the needle, which, on the one hand, can interact with the implant and, on the other hand, is provided with an actuating element, which element is constructed as an element for pressing and supporting against or on the part of the body to be treated.