The injection device of the liquid product is intended to receive an injection syringe, comprising a syringe body, with an injection needle, and a piston mounted to slide axially in the syringe body in the distal direction when an injection is given. The injection device comprises a control member of a piston intended to cooperate axially under the effect of an elastic force, with a piston rod, kinematically linked to the piston to slide. The injection device further comprises at least one member for slowing down, this member for slowing down being kinematically connected in its translational movement along the axis of the injection to the control member of the piston, the braking element being movably mounted in a control member for positioning (20) with which it cooperates with a contact between the cam of slowing down - cam path of the slowing down (102, 104), the cam of slowing down and the cam path of the slowing down (102, 104) being carried by the member for slowing down and the other by the control member for positioning (20), the cam path of the slowing down (102, 104) comprising a part of the injection (102d, 104d) such that when the cam of slowing down along the injection portion, the control member of the piston causes the piston to slide, the injection portion (102d, 104d) of the cam path of the slowing down (102, 104) comprising at least two portions respectively called fast (102r, 104r) and slow (102l, 104l), of different inclinations.Le dispositif dinjection de produit liquide est destiné à recevoir une seringue dinjection comprenant un corps de seringue, portant une aiguille dinjection, et un piston monté coulissant axialement dans le corps de seringue dans le sens distal lorsquune injection est réalisée. Le dispositif dinjection comprend un organe de commande de piston destiné à coopérer axialement, sous leffet dune force élastique, avec une tige de piston, liée cinématiquement au piston pour le faire coulisser. Le dispositif dinjection comprend en
