A medicament delivery device comprising: a housing arranged to contain a medicament container with a piston for sealing the medicament container and displacing the medicament； a medicament delivery mechanism arranged to push the piston to displace the medicament when activated； and a driving mechanism connected to the medicament delivery mechanism such that when the medicament delivery mechanism is activated, the driving mechanism converts linear motion of the medicament delivery mechanism into torque so as to rotate a rotation member.
