Communication control system and communication control method

A communication control system in which a control device and one or a plurality of control target devices are connected through a network, wherein:

• at least one of the plurality of control target devices includes a sub master and a sub slave to be synchronously controlled with each other;
• and
• the control device includes:
• a storage unit which stores each pieces of information on a synchronization period that is a period for synchronizing with the control target device, communication periods that are a plurality of periods provided during one period of the corresponding synchronization period, and mutual communication control information for enabling the sub master and the sub slave to mutually communicate in a mutual communication period shorter than the synchronization period;
• a calculation unit which calculates a control command for commanding an operation in synchronization with the control target device for each control target device;
• and
• a communication control unit which transmits the control command including the mutual communication control information to the sub master and the sub slave of the at least one control target device.