To suppress fluctuation of an optical signal level from being accumulated even when nodes are connected over multi-stages by eliminating the defect of conventional light attenuation amount control that the fluctuation of the optical signal level is accumulated.

The optical wavelength multiplexed transmission apparatus includes: a demultiplexer 12 which demultiplexes a wavelength-multiplexed optical signal into optical signals for each of wavelengths; a light attenuation amount control unit 13 which performs light attenuation amount control so as to fix the level of an optical signal of each wavelength; a multiplexer 16 which composes and multiplexes optical signals of wavelengths on which light attenuation amount control has been performed; an optical signal level storage unit 15 which stores a first level range regarding the levels of the optical signals; and a light attenuation amount control stop unit 22 which discriminates whether or not the level of the optical signal of each wavelength is settled within the first level range acquired from the optical signal level storage unit 15, and stops the light attenuation amount control onto the optical signal of the wavelength when the level is settled within the first level range.