The present invention relates to a medicament delivery device having a proximal and an opposing distal end. Said device comprises a medicament container comprising a movable plunger, a neck portion and a delivery member unit a longitudinally extending housing along a longitudinal axis A and having a proximal open end and an opposing distal open enda drive unit arranged at the distal end of the housing and configured to apply a force on the movable plunger a C-shaped tubular body comprising a longitudinally extending slit/gap such that said C-shaped tubular body can be attached to the neck portion of said medicament container forming a container unit where in said C-shaped tubular body further comprises: inner support means configured to interact with the neck portion and with the delivery member unit of said medicament container such that said medicament container is prevented from being moved in relation to the C-shaped tubular body, after the medicament container is attached to said C-shaped tubular body, and outer support means configured to interact with corresponding support means of the housing such that said C-shaped tubular body is prevented from being moved in relation to the housing after the container unit is arranged within said housing through the distal open end.
