Medicament delivery device for delivering a number of predetermined amounts of medicament, comprising - a body having a proximal and an opposite distal end and extending along a longitudinal axis; - a medicament container arranged inside said body; - a driving mechanism arranged inside said body and configured to act on said medicament container; - a manually movable activation member arranged on the distal end the body; - a biased actuator member arranged to be movable along the longitudinal axis and through the manually movable activation member, said biased actuator member being configured to protrude a predetermined distance from the distal end of the manually movable activation member and configured to interact with said driving mechanism when the biased actuator member is displaced said predetermined distance towards the proximal end of the body for delivering a predetermined amount of medicament; - an actuator guide member arranged rotatable in the body and configured to interact with the manually movable activation member and with the biased actuator member such that said actuator guide member can be held in a locked position within the body and released from said locked position after manually operating said activation member; characterized in that the actuator guide member comprises at least one second guide element adapted to interact with blocking surfaces in at least one group of guide surfaces arranged on the outer circumferential surface of the biased actuator member when said biased actuator member is manually released and is biased in the distal direction, causing a rotation of said actuator guide element, and wherein said guide element interacts with said group of guide surfaces when said biased actuator member is operated manually at the distal end of the manually movable activation member towards the proximal end of the body during displacement of the biased actuator member, causing a further rotation of said actuator guide member during delivery of medicament so as to lock the biased actuator member at the end of the delivery of medicament. - a body having a proximal and an opposite distal end and extending along a longitudinal axis; - a medicament container arranged inside said body; - a driving mechanism arranged inside said body and configured to act on said medicament container; - a manually movable activation member arranged on the distal end the body; - a biased actuator member arranged to be movable along the longitudinal axis and through the manually movable activation member, said biased actuator member being configured to protrude a predetermined distance from the distal end of the manually movable activation member and configured to interact with said driving mechanism when the biased actuator member is displaced said predetermined distance towards the proximal end of the body for delivering a predetermined amount of medicament; - an actuator guide member arranged rotatable in the body and configured to interact with the manually movable activation member and with the biased actuator member such that said actuator guide member can be held in a locked position within the body and released from said locked position after manually operating said activation member;