PURPOSE: To obtain a controller operated at a faster speed and with less power consumption than those for a conventional controller with respect to the contention controller to avoid collision of packet signals for the same destination.

CONSTITUTION: The controller is provided with N-sets of optical input terminals 31a-31d and N-sets of optical output terminals 33a-33d corresponding to the input terminals. Then N-sets of switch means 35a-35d each having a control optical input terminal 37 and reaching an optical signal passing enable state when no control light is inputted to the control optical input terminal 37 and reaching an optical signal interrupting state when the control light is received are provided between the input terminals and the output terminals. Then a control light supply system 39 supplying part of the optical signal passing through each switch means to the control optical terminal 37 of the other switch means than the switch means as the control light respectively is provided between each output terminal of the N-sets of the switch means and the control optical terminal of the other switch means except the switch means.