Disclosed is a laser radar device including optical branching couplers each of that branches a laser light oscillated, optical modulators each of that modulates a laser light after being branched, an optical combining coupler that combines laser lights modulated by the optical modulators, an optical combining coupler that combines other laser lights after being branched, an optical system that emits a composite light from the optical combining coupler, and receives lights scattered by a target, an optical combining coupler that combines the scattered lights and a composite light from the optical combining coupler, an optical detector that detects beat signals from a composite light from the optical combining coupler, a signal processing unit that extracts information about the target from the beat signals, and a diffraction grating that emits a light incident thereupon toward a specific direction according to the angle and the frequency of the incident light.