A terminal communication apparatus has a terminal communication control portion rendering an immediate communication control portion sequentially transmitting serial data to another terminal communication apparatus bitwise when receiving a packet as bitwise serial data and a normal communication control portion performing processing on the packet after accumulating the serial data until the serial data reaches a packet length when receiving the bitwise serial data switchable, performing processing with the immediate communication control portion in a case of receiving a time adjustment packet containing time adjustment data posting a timing of synchronization in the other terminal communication apparatus and performing processing with the normal communication control portion in a case of receiving a packet other than the time adjustment packet. Thus, synchronization of control object devices can be enabled without previously investigating communication delay times.