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.Autoinjecteur comportant un corps (1, 2), un réservoir (S) comportant un piston, ledit autoinjecteur comportant une tige de piston (5) déplaçable entre une position de repos et une position d'injection dans laquelle ladite tige de piston (5) a déplacé le piston du réservoir (S) pour injecter le produit fluide, un ressort (6) étant prévu pour solliciter ladite tige de piston (5) vers sa position d'injection, l'autoinjecteur comprenant un système de réglage de force (7, 8) adapté à exercer au moins une force (F2) sur ladite tige de piston (5), ladite force (F2) s'ajoutant à la force exercée par ledit ressort (6) en début d'injection, ledit système comprenant deux organes pivotants (7) coopérant avec ladite tige de piston (5), lesdits org
