A robot control apparatus allows a plurality of mobile robots to carry out tasks at a reduced or minimized cost as a whole with consideration given to costs derived from an encounter with an obstacle is provided. An action optimization controller provided in the robot control apparatus generates an instruction for optimizing actions of the plurality of mobile robots so that the plurality of mobile robots carry out the tasks at a minimized cost, based upon locomotion plan information indicative of locomotion plans of the plurality of mobile robots. A possibility that any robots have an encounter with an obstacle is determined by comparing distances from the robots to the obstacles. A locomotion plan implementation cost is calculated with consideration given to the possibility of encounter, and thus an optimum route is selected based upon the locomotion plan implementation cost with the encounter-derived cost. In accordance with the optimum route, the locomotion plan for the robot is modified.