The present disclosure relates to a medicament delivery device comprising: a housing having a proximal and distal end； a medicament container positioned in the housing and having a medicament delivery member shield； a medicament delivery mechanism associated with the medicament container； an activation member operably connected to the medicament delivery mechanism and longitudinally movable in relation to the housing from an extended position to a retracted position to activate the medicament delivery mechanism； and a removable cap assembly comprising an outer tubular cap body and an inner tubular integrity lock member coaxially coupled to the outer tubular cap body； wherein in a first position of the removable cap assembly, a resilient structure of the inner tubular integrity lock member is engaged to a first engaging structure of the activation member and a second engaging structure of the housing for preventing the activation member from moving into the retracted position.
