An object identification device identifying an image region of an identification target includes an imaging unit receiving two polarization lights and imaging respective polarization images, a brightness calculation unit dividing the two polarization images into processing regions and calculating a brightness sum value between the two polarizations images for each processing region, a differential polarization degree calculation unit calculating a differential polarization degree for each processing region, a selecting condition determination unit determining whether the differential polarization degree satisfies a predetermined selecting condition, and an object identification processing unit specifying the processing region based on the differential polarization degree or the brightness sum value depending on whether the predetermined selecting condition is satisfied and identifying plural processing regions that are specified as the processing regions as the image region of the identification target.