1. A control apparatus for a robot arm controlling a motion of the robot arm, comprising: a motion information acquiring unit that acquires motion information, from a motion information database having stored therein as the motion information in a time-oriented manner a force that the robot arm applies to an object as being corresponding to the motion; a correction motion information acquiring unit that acquires correction motion information relating to the motion information acquired by the motion information acquiring unit and as to a force that the robot arm applies, when a person corrects the motion of the robot arm by manipulating the robot arm; an environment information acquiring unit that acquires environment information being information as to the object on which the robot arm acts upon, in accordance with an environmental change reporting manipulation of the person to the robot arm; a control unit that controls the robot arm in a force control mode, such that the robot arm exerts a force control over the object with the force set in the motion information acquired by the motion information acquiring unit; a motion correction unit that corrects the motion information in accordance with the correction motion information at each time acquired by the correction motion information acquiring unit while the control unit is controlling the robot arm in the force control mode; and a control rule generating unit that generates a control rule for allowing the robot arm to automatically operate, by determining the environment information to be acquired by the environment information acquiring unit in accordance with the environmental change reporting manipulation of the person to the robot arm, and by associating the motion information corrected by the motion correction unit and the environment information acquired by the environment information acquiring unit with each other, wherein the motion of the robot arm is controlled based on the control rule generated by the control rule generating unit, while referring to the environment information acquired by the environment information acquiring unit.