Container holder assembly for use in a medicament delivery device, comprising a tubular body elongated in an axial direction, said tubular body having a proximal end and an opposite distal end, and a retaining member releasably arranged to said tubular body for securing an elongated container placed inside the tubular body, wherein said retaining member comprises a resilient structure capable of exerting an axial force on said container in said tubular body for holding the container in a fixed position inside the tubular body and wherein the retaining member and the tubular body respectively comprises a first and a second locking means capable of achieving a mutual mechanical connection, such that the retaining member is locked to the tubular body.