PURPOSE: To provide an optical communication transceiver which realizes the same performance as a conventional system regardless of the use of inexpensive parts.

CONSTITUTION: This optical communication transceiver consists of an optical bypass switch 1, an O/E transducer 4, an E/O transducer 5, and first and second bypass relays 2 and 3 controlled by a bypass control signal 10. The optical bypass switch 1 is provided with not only a B transmission line 1-b which bypasses the optical signal from an upper optical fiber main line 6-1 to a lower optical fiber main line 6-2 but also an A transmission line 1-a which sends the optical signal from the upper optical fiber main line 6-1 to the O/E transducer 4 and sends the optical signal from the E/O transducer 5 to the lower optical fiber main line 6-2. When power supply to this optical communication transceiver device is stopped, the optical transmission line of the optical bypass switch 1 is automatically switched from the A optical transmission line to the B optical transmission line.