The working characteristic and machinability of natural abrasive materials used traditionally in Japan to polish wooden proaucts were evaluated comparing with those of artificial coated abrasive paper. Natural abrasive materials investigated were leaves of Mukunoki (Aphananthe aspera Planch), integuments of Umazurahagi(Navodon modestus)and stems of Tokusa(Equisetum hiemale L. var, japonica Milde), and wood specimen abraded was padauk(Pterocarpus indicus Willd.), red sander(Pterocarpus santalinus Linn.) and ebony (Diospyros sp.). The observation of surface structure of natural abrasive materials and analysis of elements, which polish wood, contained in each materials were examined by means of X−ray microanalyzer. Then surface roughnesses(ten points average roughness), pitches of roughness, glosses and surface structure of each wood specimen polished with each natural abrasive materials and coated abrasive paper were investigated. The observation through X ray microanalyzer revealed that Silicon compounds are distributed over the cortex of leaf of Mukunoki, above all they are concentrated in needle-like hairs and processes (Fig.1), and they work to polish wood surface, and that calsium compounds are distributed over the integment of Umazurahagi, they are especially concentrated in spinules(Fig. 3) and they work to polish wood surface(Fig. 4). Glosses from specimens polished with native abrasive materials investigated are greater than those polished wtih artificial abrasive paper(Fig. 5). To evaluate the smoothness of wood surface, the pitch of surface roughness should be investigated as well as the depth of surface roughness(Fig. 9).