Described is an autoinjector (1) comprising a case (2) adapted to hold a medicament container having a needle (4)and the case (2) including a rib (2.6), a needle shroud (7) slidably disposed in the case (2) and translatable between an extended position (EP) relative to the case (2) in which the needle (4) is covered and a retracted position (RP) relative to the case (2) in which the needle (4) is exposed, and a plunger (10) slidably disposed in the case (2). The plunger (10) includes a plunger boss (10.1) adapted to abut the rib (2.6) and the needle shroud (7) when the needle shroud (7) is in the extended position (EP) and disengage the rib (2.6) when the needle shroud (7) is in the retracted position (RP) to allow the plunger (10) to translate axially relative to the case (2).描述一種自動注射器(1)，其係包括：適合保持具有一針(4)之一藥劑容器的一外殼(2)，以及該外殼(2)包括一肋條(2.6)；一針罩(7)，其係可滑動地配置於該外殼(2)中，以及相對於該外殼(2)，可在該針(4)被蓋住的一伸出位置(EP)及該針(4)露出的一縮回位置(RP)之間平移；以及可滑動地配置於該外殼(2)中的一柱塞(10)。該柱塞(10)包括一柱塞凸部(10.1)，其係適合在該針罩(7)處於該伸出位置(EP)時抵接該肋條(2.6)及該針罩(7)，以及在該針罩(7)處於該縮回位置(RP)時脫離該肋條(2.6)以允許該柱塞(10)相對於該外殼(2)軸向平移。
