1. A device for automatically setting an interlock between a plurality of robots, by editing a motion program of each robot, the device comprising: an interference area setting section for setting an interference area between the robots, using a simulation result based on the motion program of each robot; and a program editing section for inserting a motion command and a communication command before and after a command for moving each robot through the interference area of the motion program, the motion command being configured to direct the position and the orientation of each robot when the robot enters or leaves the interference area, and the communication command being configured to inform a robot of entering and leaving the interference area of the other robot.