A device for delivery of medicament, which device comprises an elongated housing; a container (4) mounted within said housing and adapted to contain liquid medicament; a stopper slidably arranged within said container; and actuating means comprising a resilient member (60), a driving means (50) having one end connected to the stopper and a second end being operably connected to the resilient member, retaining means (40) for releasably retaining said driving means in a first position where said resilient member has an accumulated energy, and activating means operably connected to said retaining means for releasing said driving means to a second position, upon actively operation by an user, such that said accumulated energy is transferred to the driving means for driving the stopper a predetermined distance within the container whereby the medicament within said container i delivered characterized in that the resilient member is a variable force spring adapted for generating a predetermined sequence of at least two different force profiles during the medicament delivery.