a liquid dispenser device for being associated with a liquid reservoir , said device comprising : a chamber provided with an inlet valve , an outlet valve , and a piston that is suitable for varying the volume of the chamber ; a liquid dispenser orifice ; and a pusher that is axially displaceable down and up between a rest position and a depressed position ; the dispenser device being characterized in that the pusher includes an elastically - deformable wall that is thus displaceable relative to the remainder of the pusher , the piston being in contact , at least momentarily , with the deformable wall , so as to be urged in displacement relative to the remainder of the pusher while the wall is being deformed , in such a manner as to open the outlet valve .