An autoinjector, comprising: - a reservoir module comprising a reservoir containing fluid and a piston, and including a needle, said reservoir module comprising an actuator sleeve that is movable relative to said reservoir between a deployed position in which it is arranged around said needle and an actuated position in which it is moved axially relative to the reservoir so as to expose the needle, - a driver module, - an interface module connecting said driver module to said reservoir module, - said driver module comprising: - a body, - a piston rod that is adapted to co-operate with the piston of said reservoir, said piston rod being movable between a rest position and an injection position in which said piston rod has moved the piston of the reservoir so as to inject the fluid through said needle, - an injection spring for urging said piston rod towards its injection position, - a lock that blocks said piston rod in its rest position, said lock comprising a thread that is connected at one end to said piston rod and at its other end to a toothed winder wheel, a locking member co-operating with a tooth of said toothed winder wheel, said locking member being movable, in particular pivotable, between a blocking position in which it prevents the winder wheel from turning in the direction of the actuation force (Fa) exerted by said injection spring on said piston rod, and an actuated position in which said turning of the winder wheel is possible, said locking member including an extension that is adapted to co-operate with said actuator sleeve when it has reached its actuated position, said autoinjector being characterized in that it includes a re-cocking knob for rewinding said thread on said winder wheel by turning said winder wheel in the opposite direction to its direction during the injection stage. - a reservoir module comprising a reservoir containing fluid and a piston, and including a needle, said reservoir module comprising an actuator sleeve that is movable relative to said reservoir between a deployed position in which it is arranged around said needle and an actuated position in which it is moved axially relative to the reservoir so as to expose the needle, - a driver module, - an interface module connecting said driver module to said reservoir module, - said driver module comprising: - a body, - a piston rod that is adapted to co-operate with the piston of said reservoir, said piston rod being movable between a rest position and an injection position in which said piston rod has moved the piston of the reservoir so as to inject the fluid through said needle, - an injection spring for urging said piston rod towards its injection position, - a lock that blocks said piston rod in its rest position, said lock comprising a thread that is connected at one end to said piston rod and at its other end to a toothed winder wheel, a locking member co-operating with a tooth of said toothed winder wheel, said locking member being movable, in particular pivotable, between a blocking position in which it prevents the winder wheel from turning in the direction of the actuation force (Fa) exerted by said injection spring on said piston rod, and an actuated position in which said turning of the winder wheel is possible, said locking member including an extension that is adapted to co-operate with said actuator sleeve when it has reached its actuated position, - a body, - a piston rod that is adapted to co-operate with the piston of said reservoir, said piston rod being movable between a rest position and an injection position in which said piston rod has moved the piston of the reservoir so as to inject the fluid through said needle, - an injection spring for urging said piston rod towards its injection position, - a lock that blocks said piston rod in its rest position, said lock comprising a thread that is connected at one end to said piston rod and at its other end to a toothed winder wheel, a locking member co-operating with a tooth of said toothed winder wheel, said locking member being movable, in particular pivotable, between a blocking position in which it prevents the winder wheel from turning in the direction of the actuation force (Fa) exerted by said injection spring on said piston rod, and an actuated position in which said turning of the winder wheel is possible, said locking member including an extension that is adapted to co-operate with said actuator sleeve when it has reached its actuated position,