An optical transceiver includes: a pseudo-random number code generator to output a signal indicating a pseudo-random number code; a digital optical transmitter to generate and transmit transmission light on the basis of the signal; an analog optical receiver to receive input light as reception light and convert the reception light into a reception signal; a transmission/reception switch to output the transmission light to one end of an optical fiber, and output light from the optical fiber to the analog optical receiver; a correlation processing unit to calculate loss curve data by performing correlation processing between the signal indicating the pseudo-random number code and the reception signal; a differential processing unit to calculate loss curve differential data on the basis of the loss curve data; and a difference calculation unit to calculate a difference between loss differential data obtained before installation of the optical fiber, and the loss curve differential data.