The present invention relates to a drug delivery device, comprising a housing (10), a drug container holder (60) configured to receive a drug container (62) having a drug delivery member (64), and an actuating device. A drive unit (81) configured to act on the drug container (62) for discharging a dose of the drug when the drive unit is discharged, and the drive unit (81) operably connected to the drive unit (81). Actuation mechanism (30, 48, 148) operable to move the drug delivery member guard (30) longitudinally movable with respect to the housing (10). The actuating mechanism comprises a force element (148) configured to bias the drug delivery member guard (30) to a proximally extended position where the drug delivery member (64) is covered. A mechanism (40, 160) is operably configured to lock the drug delivery member guard (30) in an extended position, and the locking mechanism (40, 160) is connected to the drug delivery member guard (30). , Comprising a number of locking elements (40) that are substantially radially flexible, the locking mechanism further comprising a number of shelves (160) connected to the housing, and the drug delivery member guard (30). ) Is moved to the extended position, the locking element (40) flexes radially outward, abuts the shelf surface (160), and further movement of the drug delivery member guard (30) in the distal direction. To block. The present invention is characterized by a space (158) connected to the housing (10), in which the locking element (40) is placed in an untensioned state in the delivery mode of the drug delivery device. .本発明は、薬剤送達装置に関し、薬剤送達装置は、ハウジング（１０）と、薬剤送達部材（６４）を有する薬剤容器（６２）を収容するように構成された薬剤容器ホルダ（６０）と、作動されたときに用量分の薬剤を排出するための上記薬剤容器（６２）に作用するように構成された駆動ユニット（８１）と、上記駆動ユニット（８１）に動作可能に接続され、上記駆動ユニットを作動可能な作動機構（３０、４８、１４８）とを備え、上記作動機構（３０、４８、１４８）は、上記ハウジング（１０）に対して長手方向に移動可能な薬物送達部材ガード（３０）を備え、上記作動機構は、上記薬物送達部材ガード（３０）を上記薬剤送達部材（６４）がカバーされる近位延長位置に付勢するように構成された力要素（１４８）を備え、ロック機構（４０、１６０）は上記薬物送達部材ガード（３０）を延長位置においてロックするように動作可能に構成され、上記ロック機構（４０、１６
