In order to enable more stable monitoring of communication status, a communication device is provided with: a setting unit which sets a first wavelength selected from wavelength selection alternatives included in wavelengths of light included in dummy light, and a first transmission power which is selected in accordance with a first communication status from a plurality of transmission power selection alternatives that are set in advance; a generation unit which generates light of the first wavelength from the dummy light; an adjustment unit which adjusts the light of the first wavelength to first light of the first transmission power; and a multiplexing unit which multiplexes the first light with communication light serving as light for a predetermined communication so as not to overlap each other on the time axis, and which delivers the multiplexed light to another communication device.