When the emergency stop button on the teaching pendant is pressed, the packet generating circuits 1 and 2 each prepare packet data relating to emergency stopping, and transmit this data to the robot control part by wireless communications via the transmission data switching circuit. Besides data indicating the need or lack of need for emergency stopping, a header or the like designating the packet receiving circuit to which the transmission is addressed is added to the packet data. The respective packet receiving circuits of the robot control part receive the respective sets of packet data in accordance with the designations of the headers. When the emergency stop button is pressed, emergency stop signals are output to a plurality of emergency stop control circuits from the respective packet receiving circuits immediately afterward, and a plurality of contacts connected in series are placed in a non-conductive state, so that the supply of motive force to the servo amplifiers is cut off, thus causing the robot to make an emergency stop.