An injection device comprises an actuator adapted when actuated to cause commencement of an injection sequence; a locking mechanism adapted to be moved between a locked position in which the locking mechanism prevents the actuator from being actuated, and an unlocked position in which the actuator can be actuated to cause commencement of the injection sequence. The locking mechanism comprises a contact portion which in the locked position of the locking mechanism projects against the actuator. The contact portion comprises a curved surface.