A motion editing system for a robot in which the motion of a robot edited is corrected as the movements performed by an actual robot are checked. An optional range of motion data is reproduced using an actual robot. At this time, an output from each sensor mounted to the actual robot, that is, the sensor information, is transmitted to the motion editing system. The robot's movements are evaluated on the motion editing system based on the sensor information acquired during motion reproduction. If, as a result of the robot's movements, a predetermined evaluation criterium is not met, the motion correction processing is carried out. If the predetermined evaluation criterium is met, a motion data file, in which is embedded the reference sensor information, is formulated.