An optical communication device for detecting a defect in a standby optical fiber. An active optical output unit converts an electrical signal to an optical signal, and a standby optical output unit is provided as a substitute for the active optical output unit. An optical router is connected to the active optical output unit by an active optical fiber, and is also connected to the standby optical output unit by a standby optical fiber. The optical router outputs the optical signal received from the active optical output unit to the subsequent stage, and also outputs part of the optical signal to the standby optical output unit. A defect detector detects a defect in the standby optical fiber on the basis of the light level of the optical signal output from the optical router to the standby optical output unit through the standby optical fiber.