A medicament delivery device comprises a needle for delivering a medicament; and an insertion mechanism configured to urge the needle in a first direction parallel to a longitudinal axis of the needle; wherein the insertion mechanism comprises a driving mechanism which is configured to exert a force in a second direction perpendicular to the first direction, and a cam which is coupled to the needle and is configured to receive a force from the driving mechanism and move in the first direction in response to the received force.