Abstract: A surface roughness measurement device that in one embodiment includes main and auxiliary emitting fibers, multiple collecting fibers, an optical housing, main and auxiliary reflective mirrors, and an external circuit. The optical housing includes the fibers and defines an aperture for optically contacting a surface of an object. The main reflective mirror is arranged in the optical housing, for reflecting light emitted from the main emitting fiber to a detecting point of the aperture and reflected light by the object to the collecting fibers. The auxiliary reflective mirror is arranged in the optical housing, for reflecting light emitted from the auxiliary emitting fiber to the detecting point. The external circuit is for generating a laser beam to the main and auxiliary emitting fibers, collecting the reflected light from the collecting fibers, and calculating the surface roughness of the object based on the collected reflected light.