The present invention relates to a medicament delivery device comprising a housing a medicament container (18) arranged inside said housing, a drive mechanism (14,58,12) comprising a plunger rod (12) capable of acting on a stopper (16) inside said medicament container (18) for expelling a dose of medicament, said drive mechanism further comprising a force member (14) acting on said plunger rod, an actuation mechanism capable of releasing said drive mechanism upon activation. The invention is characterised in that said actuation mechanism comprises a locking mechanism (18) capable of releasibly locking said plunger rod in any positions between an initial start position and an end position.
