There is provided a medical support arm device including a brake provided in at least one joint of a plurality of joints that define a deployment configuration of a multi-joint arm, and configured to release a rotation shaft of the at least one joint when electricity is supplied to the multi-joint arm and lock the rotation shaft when electricity is not supplied to the multi-joint arm. When electricity is not supplied the brake is configured to exert a brake force that supports a weight of the multi-joint arm to maintain the deployment configuration of the multi-joint arm, but also permits rotation of the rotation shaft by an external manually applied force equal to or larger than a predetermined value