A transmission device includes a current transmission right as a node constituting an implicit token-passing network. When receiving a synchronization frame including a synchronization node number for specifying a synchronization node and network live node map information, which is information on nodes present in the network, or a reminder frame including a transmission right node number for specifying a node having a transmission right and network live node map information, which is information on the nodes present in the network, the transmission device is configured to transmit a data frame, and after the transmission of the data frame, transmit a completion frame including a transmission node number for specifying a node of a transmission source and network live node map information, which is information on the nodes present in the network.