Disclosed is a laser processing device including a laser light source configured to output laser light, a converging unit configured to converge the laser light toward a first surface to form a converging point, a camera configured to image reflected light of the laser light from the first surface, a spatial light modulator for modulating the laser light according to a modulation pattern, and a controller configured to execute acquisition processing of applying the laser light to the first surface by controlling the laser light source and imaging the reflected light by controlling the camera to acquire a reflectance of the first surface for the first wavelength.