A lidar apparatus for vehicles, comprising: a transmission unit configured to output a beam, wherein the transmission unit comprises: a light generation unit configured to generate transmission light that contains the beam; a first beam steering unit configured to steer the beam in a first direction; and a second beam steering unit configured to steer the beam in a second direction which is perpendicular to the first direction; a reception unit configured to acquire reflection light formed as a result of the beam being reflected by an object; and a processor configured to generate information about the object based on the reflection light, and control at least one of the first beam steering unit or the second beam steering unit to adjust an angle of beam steering of the transmission light based on the generated information about the object, wherein the first beam steering unit comprises an Arrayed Waveguide Grating, AWG, wherein the AWG comprises: an optical splitter configured to split the transmission light, a Free Propagation Region, FPR, configured to combine the split light and output the combined light, and a wave guide unit configured to guide the split light to the FPR, wherein the transmission unit comprises: at least one of a heater and a piezoelectric unit, wherein the heater is configured to provide heat to the wave guide unit based on an electrical signal to change individual phases of beams of the split light, wherein the piezoelectric unit is configured to apply pressure to the wave guide unit to change individual phases of beams of the split light, and wherein the second beam steering unit comprises a plurality of grating couplers which are arranged to respectively correspond to a plurality of output optical paths of the AWG, wherein each of the plurality of grating couplers comprises: a grating region including a plurality of lines and a plurality of grooves distinguishing the plurality of lines, and a transition region being formed such that the more distant the transition region from the grating region, the narrower the transition region is, wherein one end of the transition region is connected to the first beam steering unit and other end of the transition region is connected to the grating region, wherein each of the plurality of grating couplers is configured to change an emission angle of the beam when the processor adjusts a wavelength of the transmission light. a light generation unit configured to generate transmission light that contains the beam; a first beam steering unit configured to steer the beam in a first direction; and a second beam steering unit configured to steer the beam in a second direction which is perpendicular to the first direction; a reception unit configured to acquire reflection light formed as a result of the beam being reflected by an object; and a processor configured to generate information about the object based on the reflection light, and control at least one of the first beam steering unit or the second beam steering unit to adjust an angle of beam steering of the transmission light based on the generated information about the object, wherein the first beam steering unit comprises an Arrayed Waveguide Grating, AWG, wherein the AWG comprises: an optical splitter configured to split the transmission light, a Free Propagation Region, FPR, configured to combine the split light and output the combined light, and a wave guide unit configured to guide the split light to the FPR, wherein the transmission unit comprises: at least one of a heater and a piezoelectric unit, wherein the heater is configured to provide heat to the wave guide unit based on an electrical signal to change individual phases of beams of the split light, wherein the piezoelectric unit is configured to apply pressure to the wave guide unit to change individual phases of beams of the split light, and wherein the second beam steering unit comprises a plurality of grating couplers which are arranged to respectively correspond to a plurality of output optical paths of the AWG, wherein each of the plurality of grating couplers comprises: a grating region including a plurality of lines and a plurality of grooves distinguishing the plurality of lines, and a transition region being formed such that the more distant the transition region from the grating region, the narrower the transition region is, wherein one end of the transition region is connected to the first beam steering unit and other end of the transition region is connected to the grating region, wherein each of the plurality of grating couplers is configured to change an emission angle of the beam when the processor adjusts a wavelength of the transmission light. a grating region including a plurality of lines and a plurality of grooves distinguishing the plurality of lines, and a transition region being formed such that the more distant the transition region from the grating region, the narrower the transition region is, wherein one end of the transition region is connected to the first beam steering unit and other end of the transition region is connected to the grating region, wherein each of the plurality of grating couplers is configured to change an emission angle of the beam when the processor adjusts a wavelength of the transmission light.