Node equipment 1, having optical attenuator unit 21 for optically attenuating wavelength division multiplexing signals received and optical multiplexer/demultiplexer unit 5 for performing optical multiplexing/demultiplexing of the wavelength division multiplexing signals received from the optical attenuator unit 21 via an optical cord 11, includes: output level detecting unit 24 for detecting the optical power level of the wavelength division multiplexing signals at a pre-stage of the optical cord 11; input level detecting unit 52 for detecting the optical power level of the wavelength division multiplexing signals at a post-stage of the optical cord 11; deciding unit 25 for deciding abnormality of the optical power level loss through the optical cord 11 from the optical power levels detected by the output level detecting unit 24 and input level detecting unit 52; and control unit 26 for controlling the optical attenuation of the optical attenuator unit 21 according to the abnormality decision result by the deciding unit 25.