PURPOSE: To detect a wind far apart in the atmosphere with a simple and compact structure by a method wherein the structure is made so as to measure a Doppler shift for a tail part of a reception signal of a pulse part reflected by the target.

CONSTITUTION: Laser beams 14 emitted from a single pulsing laser source 12 comprises a high strength pulse part and a low strength tail part, and the pulse part is transmitted along a propagation path 22 by a switch function of a sound-optical modulator 20, and radiated to the atmosphere via a transmitter/receiver telescope 40. A reception signal 26 of the pulse part reflected by a target like an aerosol is incident on a heterodyne detector 28 through a polarized beam splitter 30. Further, after the tail part of each pulse transmitted along a propagation path 24 is converted 39 in biased waves from vertically to horizontally in order to correspond to the reception signal 26, the propagation path is transferred 32 to be coupled to the signal 26. A Doppler shift of the signal 26 for the tail signal is measured by the detector 28, measured data are digitalized and processed 50, so that disorder of an air in the atmosphere is detected.