A transfer device for coupling a priority signal and a standard signal includes a reception unit configured to receive a plurality of signals transmitted from a device connected to a path different from a forwarding path, a separation unit configured to separate the signals into the priority signal and the standard signal, an identifier reference unit configured to reference an identifier added to the standard signal, an identifier sort unit configured to sort the standard signal by the identifier, a signal coupling unit configured to couple the plurality of standard signals, a multiplexing unit configured to multiplex the priority signal and the standard signal, a priority control unit configured to determine a transfer order of the signals, a transmission unit configured to transmit the signals to a device connected to the forwarding path, an interrupt transfer processing unit configured to perform interrupt processing in a case where the priority signal arrives during transfer of the standard signal, a signal division unit configured to divide the standard signal, an identifier addition unit configured to add the identifier to the standard signal divided, and a transmission suspending unit configured to suspend transfer of the standard signal until transfer of the priority signal is completed.