A medical manipulator system having: an end effector configured to be controlled to perform a treatment; an arm to which the end effector is attached, wherein the arm has a plurality of movable parts, wherein the plurality of movable parts are configured to be moved under one of a plurality of modes, wherein each of the plurality of modes comprises a combination of: movement by one or more actuators; and movement by an external force; and a controller configured to: control the end effector to perform the treatment; and select the one of the plurality of modes; and effect movement of the plurality of movable parts by controlling the one or more actuators and by permitting movement by the external force in accordance with the one of the plurality of modes selected.