An autoinjector having a lower body (10) receiving a reservoir, a piston, a needle, a central body (1) fixed to the lower body, an actuating sleeve (11) having a contact end to contact the body of the user and displaceable in the lower body between a projected position, in which the actuating sleeve at least partially projects out of the lower body and an actuation position, in which the actuating sleeve is axially displaced towards the interior of the lower body. The actuating sleeve includes a flexible tab (110) adapted to deform on the one hand radially and on the other hand laterally relative to the central body when the actuating sleeve is displaced from its projected position towards its actuation position then from its return actuation position towards its projected position.
