Optical non-contact detection of the surface roughness of felts was successfully realized by the use of an optical fiber bundle and a photosensor. Experiments done on various kinds of felts revealed that the visual evalua-tion of roughness by human judgement had high correlation with the estimation by this optical method but not with that by the conventional friction method using a surface tester. The present technique was verified to offer a method to measure the surface irregularity of felts which is objective in contrast to visual judgement, as well as more reliable than the friction method that may perturb the natural states of surface tested.