An inspection apparatus comprising: a structured-light source , at least one lens and an image sensor configured to sequentially perform an operation a plurality of times for each of a plurality of structured lights having light brightness patterns that correspond to the same phase range, the operation including: radiating, by the structured-light source , a structured light of the plurality of structured lights; adjusting, by the at least one lens , an optical path of the structured light such that each light beam of the structured light corresponding to each phase of the phase range is uniformly radiated via a fist diaphragm to a whole target region on a surface of an object; and capturing, by the image sensor , a reflected light generated by the structured light being reflected from the target region and passed through a second diaphragm ; and a processor electrically connected to the structured-light source , the at least one lens and the image sensor , the processor being configured to: acquire light quantity values of a plurality of reflected lights generated by the plurality of structured lights and captured by the image sensor ; and derive an angle of the target region of the object with respect to a reference plane by deriving phase values of the plurality of reflected lights, based on the light quantity values of the plurality of reflected lights. a structured-light source , at least one lens and an image sensor configured to sequentially perform an operation a plurality of times for each of a plurality of structured lights having light brightness patterns that correspond to the same phase range, the operation including: radiating, by the structured-light source , a structured light of the plurality of structured lights; adjusting, by the at least one lens , an optical path of the structured light such that each light beam of the structured light corresponding to each phase of the phase range is uniformly radiated via a fist diaphragm to a whole target region radiating, by the structured-light source , a structured light of the plurality of structured lights; adjusting, by the at least one lens , an optical path of the structured light such that each light beam of the structured light corresponding to each phase of the phase range is uniformly radiated via a fist diaphragm to a whole target region on a surface of an object; and capturing, by the image sensor , a reflected light generated by the structured light being reflected from the target region and passed through a second diaphragm ; and a processor electrically connected to the structured-light source , the at least one lens and the image sensor , the processor being configured to: acquire light quantity values of a plurality of reflected lights generated by the plurality of structured lights and captured by the image sensor ; and derive an angle of the target region of the object with respect to a reference plane by deriving phase values of the plurality of reflected lights, based on the light quantity values of the plurality of reflected lights. acquire light quantity values of a plurality of reflected lights generated by the plurality of structured lights and captured by the image sensor ; and derive an angle of the target region of the object with respect to a reference plane by deriving phase values of the plurality of reflected lights, based on the light quantity values of the plurality of reflected lights. <EOS>