Abstract: Provided are a control apparatus, a control system, and a control method for controlling a work machine which reduce inadvertent contact during operation of the work machine and inhibit a decrease in operating rate. A control apparatus for controlling a work machine having a movable part includes: an acquisition means of acquiring state information indicating a posture of the work machine, action information indicating an action of the work machine, and surrounding information indicating an arrangement of a surrounding object around the work machine; a specification means of specifying, based on the state information and the action information, a safe distance that is set between the movable part and the surrounding object; and an action control means of controlling an action of the work machine in accordance with the safe distance and the surrounding information.