An optical transmission device includes: a controlled oscillator for outputting a calibration signal having an output frequency that corresponds to an input oscillation control signal; an electrical-to-optical conversion circuit for generating an optical transmission signal by superimposing a transmission signal in a radio frequency band and the calibration signal on an optical wave; an optical input and output unit for sending the optical transmission signal to an optical transmission path and receiving a reflection signal that is a part of the optical transmission signal from an optical reception device; an optical-to-electrical converter for converting the reflection signal into a radio frequency signal; a phase locked loop for generating the oscillation control signal so that radio frequency output of the optical-to-electrical converter is phase-locked with a reference signal input from a reference signal source; and a signal generation circuit for generating, as the transmission signal, the radio frequency signal phase-locked with the calibration signal.