A cap assembly for a medicament delivery device having a housing and a medicament container holder. The cap assembly includes a retainer member connectable to the container holder a hub having a needle and coaxially movable within the retainer member an inner cap connected to the hub and the retainer member an outer cap coaxially arranged to the inner cap and a cap clutch mechanism having a locking member that is axially movable in relation to the inner and outer caps between a disengaged position, in which the outer cap is rotatable relative to the inner cap, and an engaged position, in which the outer cap is rotationally locked to the inner cap. The cap clutch mechanism also has a clutch biasing device arranged between the outer cap and the locking member for biasing the locking member for keeping it in the disengaged position.
