A transmitting device, comprising: an N number of input interfaces each being identified with a frame number, each of which receives an M number of time division multiplexing signals of the corresponding frame, from a first device, and outputs a TDM aggregate signal in which an M number of timeslots are arranged sequentially in line along a time axis by performing time division multiplexing the received M number TDM signals, N and M being an integer of two or more; an N number of output interfaces each being identified with a frame number, each of which transmits an M number of TDM signals to a second device; a multiplexing unit which receives the N number of TDM aggregate signals from the N number of input interfaces, and generates, with respect to each of a plurality of channels, a TDM-multiplexing signal by arranging an N number of timeslots corresponding to said channel, of the N number of TDM aggregate signals, sequentially in line along the time axis; a distributing unit which transmits to each of the N number of output interfaces the same M number of TDM-multiplexing signals generated by the multiplexing unit; and a TDM transmission path which transmits the same M number of TDM-multiplexing signals generated by the multiplexing unit to the distributing unit, wherein each of the N number of output interfaces comprises a table storage unit which stores a switching table in which a transmission destination of each TDM signal and its frame number are defined, and each of the N number of output interfaces is adapted, when receiving a TDM-multiplexing signal from the distributing unit, extracts the M number of TDM signals from the TDM-multiplexing signal according to its frame number stored in the switching table, and transmits the extracted M number of TDM signals to transmission destinations according to the transmission destinations stored in the switching table. an N number of input interfaces each being identified with a frame number, each of which receives an M number of time division multiplexing signals of the corresponding frame, from a first device, and outputs a TDM aggregate signal in which an M number of timeslots are arranged sequentially in line along a time axis by performing time division multiplexing the received M number TDM signals, N and M being an integer of two or more; an N number of output interfaces each being identified with a frame number, each of which transmits an M number of TDM signals to a second device; a multiplexing unit which receives the N number of TDM aggregate signals from the N number of input interfaces, and generates, with respect to each of a plurality of channels, a TDM-multiplexing signal by arranging an N number of timeslots corresponding to said channel, of the N number of TDM aggregate signals, sequentially in line along the time axis; a distributing unit which transmits to each of the N number of output interfaces the same M number of TDM-multiplexing signals generated by the multiplexing unit; and a TDM transmission path which transmits the same M number of TDM-multiplexing signals generated by the multiplexing unit to the distributing unit, wherein each of the N number of output interfaces comprises a table storage unit which stores a switching table in which a transmission destination of each TDM signal and its frame number are defined, and each of the N number of output interfaces is adapted, when receiving a TDM-multiplexing signal from the distributing unit, extracts the M number of TDM signals from the TDM-multiplexing signal according to its frame number stored in the switching table, and transmits the extracted M number of TDM signals to transmission destinations according to the transmission destinations stored in the switching table.