A wavelength division multiplexing transmission apparatus including a plurality of transponders for converting optical signals from wideband wavelengths to narrowband wavelengths, and a monitoring control unit for controlling the transponders, each of the transponders comprising:
- an assigned wavelength determining unit configured to convert channel information specified by the monitoring control unit to assigned wavelength information assigned to the transponder;
- and
- a full-band tunable laser (FBTL) optical module control unit configured to control a full-band tunable laser (FBTL) optical module in such a manner as to output the optical signal, based on the assigned wavelength information after conversion by the assigned wavelength determining unit.