An autoinjector having a lower body receiving a tank containing fluid product and a piston and a needle. The autoinjector including a central body fastened to the lower body and an actuating sleeve provided with a contact end that contacts the body of the user, the actuating sleeve moveable between a projected position and an actuation position. The actuating sleeve is in a projected position prior to and after actuation of the autoinjector, an injection mechanism is provided to inject the fluid product through the needle when the needle is in an injection position in which it is inserted in the body of the user. The autoinjector includes a tank movement device to move the needle towards the injection position, the tank movement device triggering the injection mechanism only after the needle has reached its injection position.