Router having a function to prevent a packet sequence inversion

A router includes a plurality of control units connected in parallel, each having an input connected to a receiving interface and an output connected to a transmitting interface, and performing timing control of outgoing packets to the transmitting interface based on header information of incoming packets, the incoming packets being stored in a memory and the stored packets being transmitted to the transmitting interface in order of transmission of the outgoing packets. A distributing unit distributes transmitting sequence information, related to the stored packets in the memory, to other control units. The distributing unit determines whether a packet sequence inversion in the control unit occurs, based on a result of comparison of the transmitting sequence information received and the transmitting sequence information held by the control unit, inhibiting the transmission of the stored packets to the transmitting interface when the packet sequence invention is detected.