Manual injection device comprising a lower body (1) receiving a reservoir (S) containing the fluid product to be injected, a piston (P) and a needle (A), an upper body (2) that is axially movable relative to the lower body (1) upon actuation, the upper body (2) having a piston rod (TP) cooperating with the piston (P) during injection to move the latter in the reservoir (S), an actuator sleeve (10) having a contact end (11) for contacting the user's body and being movable, relative to the lower body (1), between projecting positions in which said actuator sleeve (10) at least partially projects from the lower body (1) and an actuation position in which the actuator sleeve (10) is moved axially towards the inside of the lower body (1), wherein the actuator sleeve (10) is in a first projecting position prior to actuation of the manual injection device, and in a second projecting position following actuation of the manual injection device, the actuator sleeve (10) defining, with the lower body (1) or with any element rigidly connected to said lower body, such as a reservoir holder, a pricking lock, and the piston rod (TP) defining, with the reservoir (S) or with any element rigidly connected to said reservoir (S), such as a reservoir holder or the lower body (1), an injection lock, the force required for axially moving the pricking lock being less than the force required to actuate the injection lock, such that the pricking lock is actuated before the injection lock.Dispositif d'injection manuelle comportant un corps inférieur (1) recevant un réservoir (S) contenant du produit fluide à injecter, un piston (P) et une aiguille (A), un corps supérieur (2) axialement déplaçable par rapport audit corps inférieur (1) lors de l'actionnement, ledit corps supérieur (2) comportant une tige de piston (TP) coopérant avec ledit piston (P) lors de l'injection pour le déplacer dans le réservoir S, un manchon actionneur (10) comportant une extrémité de contact (11) destinée à venir en
