A Medicament delivery device comprises: a tubular housing having a proximal end and an opposite distal end； an injection drive configured to exert force on a medicament container to expel medicament； and an injection drive holder configured to releasably hold the injection drive in a pre-tensioned state before injection of the medicament. The injection drive holder comprises a tubular extension part for receiving the injection drive to be axially movable therein and a release ring coaxially arranged on the tubular extension part, the release ring being axially movable between proximal and distal positions along the outer surface of the tubular extension part. The tubular extension part is configured to engage with the injection drive when the release ring is at the proximal position and release the injection drive as the release ring moves distally leaving the proximal position.藥物輸送裝置包括：管狀外殼，具有近側端及相反的遠側端；注射驅動器，被建構成施力在藥物容器上，以排出藥物；及注射驅動器夾具，被建構成在該藥物的輸送之前於先繃緊狀態中可釋放地固持該注射驅動器。該注射驅動器夾具包括一管狀延伸零件，用於在其中承納可被軸向地運動的注射驅動器，及一同軸向地配置在該管狀延伸零件上之釋放環件，該釋放環件係可於近側及遠側位置之間沿著該管狀延伸零件的外表面軸向地運動。該管狀延伸零件被建構成當該釋放環件係在該近側位置時與該注射驅動器嚙合，且當該釋放環件朝遠側地運動離開該近側位置時釋放該注射驅動器。
