PURPOSE: To suppress a loss of an optical signal, and to execute a switching operation at a high speed by constituting the titled device so that a control means outputs a control signal to a switching means, switches an optical path, and photodetects a data signal, when an address code which has been added in front of the data signal coincides with an address code which has been added to the switching means.

CONSTITUTION: A branch light beam to an optical/electric transducer 21 side by a half mirror 31, namely, the first input optical signal IN1 is converted to an electric signal by the optical/electric transducer 21 and amplified by an amplifier 22, and inputted to an address code coincidence detector 23. A coincidence detection to an address code which has been added in advance, of each optical switch is executed, and when each of them coincides, the address code coincidence detector 23 outputs a coincidence signal to a switch controller 24. The switch controller 24 drives the optical switch concerned 10, switches an optical path from OUT2 to OUT1 and makes a data signal branch. When the address code is discrepant, the optical switch 10 is not driven, the data signal is outputted from the optical path OUT2, and it is made to transmit through the optical switch 10.