Provided is a control device comprising a communication management part and a user application processing part. The user application processing part is for detecting slave devices, which are communication targets of control data having been set using a setting tool, and the slave devices are connected to a filed bus. The communication management part is for managing the communication of the control data in accordance with a control cycle. The communication management part determines 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.