The invention relates to an autoinjector comprising a body (1 2) a vessel (S) comprising a piston said autoinjector comprising a piston rod (5) movable between an inoperative position and an injection position in which said piston rod (5) has moved the piston of the vessel (S) in order to inject the fluid product a spring (6) being provided such as to bias said piston rod (5) toward the injection position thereof the autoinjector including a force adjustment system (7 8) suitable for exerting at least one force (F2) on said piston rod (5) said force (F2) adding to the force exerted by said spring (6) at the start of the injection said system including two pivoting members (7) engaging with said piston rod (5) said pivoting members (7) being connected to one another by two resilient elements (8) said body (1 2) comprising a handle (3) said pivoting members (7) being mounted such as to pivot on said handle (3) about stationary shafts (79) said autoinjector including an end of injection indicator consisting of and/or secured to said handle (3) and comprising an indication portion which is movable and/or deformable relative to said body (1 2) such as to engage after the end of the injection with at least one viewing window.
