The present invention is to provide a wavelength cross-connect device that reduces device costs.
A wavelength cross-connect device 10B performs relaying for changing, using WSSs, routes of optical signals transmitted from M routes 1h to Mh, in which K optical fibers 1f to Kf are grouped for each of the routes, on an input side to output the optical signals to respective optical fibers 1f to Kf of M routes 1h to Mh on an output side. Input ports of each of the optical couplers 25a to 26d are connected to output ports of each of first WSSs 21a to 22k. Further, the input ports of each of the optical couplers 25a to 26d are connected to the output ports of the first WSSs 21a to 22k and output ports of each of the optical couplers 25a to 26d are connected to input ports of second WSSs 23a to 24k such that the optical signals input from the optical fibers 1f to Kf in each of the routes 1h to Mh on the input side are capable of being output to the optical fibers 1f to Kf in each of the routes 1h to Mh on the output side, respectively.