Described is an autoinjector (1) comprising a case (2) having a rib (2.9), a needle shroud (7) telescopically coupled to the case (2) and movable between a first extended position (EP), 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), and a collar (16) rotatably and slidably disposed in the case (2) and coupled to the needle shroud (7) and the carrier (8). The collar (16) abuts the rib (2.9) when the needle shroud (7) is in the first extended position (EP) and the carrier (8) is in the first axial position, and the collar (16) disengages the rib (2.9) when the needle shroud (7) is in the retracted position (RP) and the carrier (8) is in the second axial position.本發明關於一種自動注射器(1)，其係包括：有一肋條(2.9)的一外殼(2)；一針罩(7)，其係可伸縮地耦合至該外殼(2)以及可在一第一伸出位置(EP)、一縮回位置(RP)及一鎖定第二伸出位置(SEP)之間移動；可滑動地設置於該外殼(2)中的一載具(8)，其係適用於保持一藥劑容器，以及相對於該外殼(2)可從一第一軸向位置移到一第二軸向位置；以及一軸環(16)，其係可旋轉及可滑動地配置於該外殼(2)中以及耦合至該針罩(7)及該載具(8)。在該針罩(7)處於該第一伸出位置(EP)以及該載具(8)處於該第一軸向位置時，該軸環(16)抵接該肋條(2.9)，以及在該針罩(7)處於該縮回位置(RP)以及該載具(8)處於該第二軸向位置時，該軸環(16)脫離該肋條(2.9)。
