In a control method by a robot system, in the robot system including a plurality of robots and a teaching device connected to the plurality of robots via a network, the teaching device transmits, to an identification act execution robot among the plurality of robots, an identification act instruction signal for causing the identification act execution robot to perform an identification act of identifying a transmission target robot to which operation data is planned to be transmitted among the plurality of robots, the identification act execution robot, which receives the identification act instruction signal, performs the identification act, and, after the identification act execution robot performs the identification act, when the identification act execution robot and the transmission target robot are the same, the teaching device transmits the operation data to the transmission target robot.