The present invention relates to a cap assembly to be used with a medicament delivery device, which medicament delivery device comprises a housing and a medicament container holder(20), said cap assembly comprising a retainer member (134) connectable to the medicament container holder, a hub (148)comprising a needle (152) having a proximal end (154) and a distal end (156), said hub being coaxially movable within the retainer member, a removable inner cap (146) interactively connected to the hub (134) and to the retainer member (134), a removable outer cap (132)being coaxially arranged to the inner cap, and a cap clutch mechanism (166) comprising a locking member (168) which is axially movable in relation to said inner and outer caps between a disengaged position in which said locking member is disconnected from the outer and the inner cap such that the outer cap is rotatable in relation to said inner cap and an engaged position in which said locking member is connected to the outer and to the inner cap such that the outer cap is rotationally locked to the inner cap. The invention is characterised in that the cap clutch mechanism (166) further comprises clutch biasing means (180) arranged between the outer cap and the locking member, said clutch biasing means (180) being capable of biasing the locking member for keeping it in the disengaged position.
