A laser radar device comprising: an optical transmission unit for transmitting a pulse-modulated optical signal having a high time period and a low time period, wherein a level of continuous wave light is output in the low time period as a low-level component of a pulse; a circulator for transmitting the optical signal as transmission light and acquiring reflection light from a target in an atmosphere as reception light; an optical partial reflecting unit for reflecting the optical signal, this reflected optical signal being an input to the circulator , the optical partial reflecting unit being provided on a path through which the transmission light is transmitted from the circulator to the atmosphere; and a detection unit for performing coherent detection on the reception light using, as local light, a signal in a low time period of the optical signal reflected by the optical partial reflecting unit, wherein the detection unit comprises: a light receiving element for performing coherent detection on the local light and the reception light and converting a result of the coherent detection to a current signal; a current-voltage converter for converting the current signal from the light receiving element into a voltage signal; and a signal processor for performing frequency analysis on the voltage signal from the current-voltage converter, wherein a reflectance in the optical partial reflecting unit is controlled by the signal processor . an optical transmission unit for transmitting a pulse-modulated optical signal having a high time period and a low time period, wherein a level of continuous wave light is output in the low time period as a low-level component of a pulse; a circulator for transmitting the optical signal as transmission light and acquiring reflection light from a target in an atmosphere as reception light; an optical partial reflecting unit for reflecting the optical signal, this reflected optical signal being an input to the circulator , the optical partial reflecting unit being provided on a path through which the transmission light is transmitted from the circulator to the atmosphere; and a detection unit for performing coherent detection on the reception light using, as local light, a signal in a low time period of the optical signal reflected by the optical partial reflecting unit, wherein the detection unit comprises: a light receiving element for performing coherent detection on the local light and the reception light and converting a result of the coherent detection to a current signal; a current-voltage converter for converting the current signal from the light receiving element into a voltage signal; and a signal processor for performing frequency analysis on the voltage signal from the current-voltage converter, a light receiving element for performing coherent detection on the local light and the reception light and converting a result of the coherent detection to a current signal; a current-voltage converter for converting the current signal from the light receiving element into a voltage signal; and a signal processor for performing frequency analysis on the voltage signal from the current-voltage converter, <EOS>