A control device , comprising: a user application processing part configured to detect slave devices , which are communication targets of control data having been set using a setting tool, and the slave devices are connected to a field bus ; and a communication management part configured to perform communication management conforming to a control cycle of the control data, a control part configured to execute operation control of the communication management part and the user application processing part , the communication management part comprises a control cycle determination part configured to determine the control cycle using a pre-stored propagation delay time for each of the slave devices that are the communication targets of the control data, the control part configured to execute a process of generating transmission data by the user application processing part , a process of communication by the communication management part , and a process of analyzing received data in the control data by the user application processing part in this order, on the basis of a process of generating the transmission data in the control data by the user application processing part , the control device and the slave devices are connected to one other by a field network and the control device and the slave devices perform communication of control data using the field bus via the field network, the communication management part comprises a propagation delay time measurement part configured to measure the propagation delay time, the propagation delay time is stored in association with a type of a slave device, and that the propagation delay time includes an outbound propagation delay time and a return propagation delay time. a user application processing part configured to detect slave devices , which are communication targets of control data having been set using a setting tool, and the slave devices are connected to a field bus ; and a communication management part configured to perform communication management conforming to a control cycle of the control data, a control part configured to execute operation control of the communication management part and the user application processing part , the communication management part comprises a control cycle determination part configured to determine the control cycle using a pre-stored propagation delay time for each of the slave devices that are the communication targets of the control data, the control part configured to execute a process of generating transmission data by the user application processing part , a process of communication by the communication management part , and a process of analyzing received data in the control data by the user application processing part in this order, on the basis of a process of generating the transmission data in the control data by the user application processing part , the control device and the slave devices are connected to one other by a field network and the control device and the slave devices perform communication of control data using the field bus via the field network, the communication management part comprises a propagation delay time measurement part configured to measure the propagation delay time, the propagation delay time is stored in association with a type of a slave device, and that the propagation delay time includes an outbound propagation delay time and a return propagation delay time. <EOS>