A multiple input/output wavelength selective switch device 1 is configured of an N×M optical cross connect switch 10, wavelength selector 20 and controller 40. The N×M optical cross connect switch 10 turns WDM signals of N channels inputted to input routes Rin1 to RinN into M WDM signals. The wavelength selector 20 can perform a selection operation with respect to each of the M WDM signals according to their wavelengths and output the signals from output routes Rout1 to RoutM.