A configuration is provided which includes: a reference light source to emit laser light; an optical phase modulator to perform phase modulation of transmission light of the laser light on the basis of a linear-phase-modulation signal having a first frequency component and a second frequency component; an optical intensity modulator to modulate light intensity of the transmission light on the basis of a pulsed light generation signal for generation of pulsed light; first and second optical antennas to emit the transmission light to a space and receive reflected light from a first point and a second point; an optical receiver to perform heterodyne detection on light obtained by mixing received light and local oscillation light; and a signal processor to separate a received signal on the basis of the first and the second frequency components.