Medicament delivery device comprising: - a generally elongated housing, which housing comprises a proximal housing part and a distal housing part arranged and mounted to be movable relative each other; - a drive force mechanism, comprising a plunger rod, a drive force spring and a drive member, which drive force mechanism is accommodated in said distal housing part and being slidably arranged in relation to the distal housing part, and wherein the drive member comprises releasable means and the plunger rod comprises counter releasable means which interact together for releasably engaging the plunger rod to the drive member; - a container filled with medicament arranged within said proximal housing part; - a holding member operably connected to said drive force mechanism for holding said drive force mechanism in a loaded state and wherein said holding member is arranged to be axially moved in relation to the distal housing part a predetermined distance towards a distal end of the device by the proximal housing part when said housing parts are moved towards each other; - an actuation member configured to be biased in relation to the distal housing part from a non-operating position in which the actuation member partially protrudes from the distal housing part to an operating position in which the actuation member is confined within the distal housing, and wherein said actuation member is operably connected to said drive force mechanism for releasing the drive force mechanism from its loaded state; - wherein the proximal housing part comprises a co-acting means and the holding member comprises a counter co-acting means which interact together for moving the holding member in relation to the distal housing part a predetermined distance towards a distal end of the device characterised in that - said actuation member is resiliently connected to the distal housing part such that said actuation member is always recoiled after being biased regardless of whether the actuation mechanism is released; and in that - said drive force mechanism is configured to be released from its loaded state only after the holding member is axially moved in relation to the distal housing part and the actuation member is biased from the non-operating to the operating position. - a generally elongated housing, which housing comprises a proximal housing part and a distal housing part arranged and mounted to be movable relative each other; - a drive force mechanism, comprising a plunger rod, a drive force spring and a drive member, which drive force mechanism is accommodated in said distal housing part and being slidably arranged in relation to the distal housing part, and wherein the drive member comprises releasable means and the plunger rod comprises counter releasable means which interact together for releasably engaging the plunger rod to the drive member; - a container filled with medicament arranged within said proximal housing part; - a holding member operably connected to said drive force mechanism for holding said drive force mechanism in a loaded state and wherein said holding member is arranged to be axially moved in relation to the distal housing part a predetermined distance towards a distal end of the device by the proximal housing part when said housing parts are moved towards each other; - an actuation member configured to be biased in relation to the distal housing part from a non-operating position in which the actuation member partially protrudes from the distal housing part to an operating position in which the actuation member is confined within the distal housing, and wherein said actuation member is operably connected to said drive force mechanism for releasing the drive force mechanism from its loaded state; - wherein the proximal housing part comprises a co-acting means and the holding member comprises a counter co-acting means which interact together for moving the holding member in relation to the distal housing part a predetermined distance towards a distal end of the device characterised in that - said actuation member is resiliently connected to the distal housing part such that said actuation member is always recoiled after being biased regardless of whether the actuation mechanism is released; and in that - said drive force mechanism is configured to be released from its loaded state only after the holding member is axially moved in relation to the distal housing part and the actuation member is biased from the non-operating to the operating position.