Described is an autoinjector (1) comprising a case (2) including a rib (2.3), a needle shroud (7) telescopically coupled to the case (2) and movable between a first extended position (FEP), a retracted position (RP) and a locked second extended position (SEP), a carrier (8) slidably arranged in the case (2), adapted to hold a medicament container, and movable from a first axial position to a second axial position relative to the case (2), a collar (16) rotatably and slidably disposed in the case (2) and coupled to the needle shroud (7) and the carrier (8), and a trigger button (13) operably coupled to the carrier (8). The carrier (8) abuts the rib (2.3) in the first axial position and the needle shroud (7) is in the first extended position (FEP) and disengages the rib (2.3) when the needle shroud (7) is in the retracted position (RP) and the trigger button (13) is pressed to advance the carrier (8) to the second axial position.