Disclosed is an optical communication line monitoring apparatus comprising: an optical transceiver for transmitting management frames to remote devices connected to optical communication lines and receiving response frames transmitted from the remote devices; an optical time domain reflectometer (OTDR) for transmitting optical pulse signals to the optical communication lines and detecting reflection signals reflected from the optical communication lines, which have received the optical pulse signals; an optical switch for switching the optical transceiver and the OTDR at an input terminal thereof and switching each of multiple optical communication lines at an output terminal thereof; and a monitoring unit for determining whether or not a first optical communication line is abnormal based on a response frame transmitted from a first remote device, with the input terminal connected to the optical transceiver and the output terminal connected to the first optical communication line among the multiple optical communication lines.