Tomakomai Paper mill, vitrified artifical pulpstone was employed for the first time in our country, on May, 1949. On this report, at first, comparative groundwood with usual cement artifical pulpstone, natural stone, and pulpstone, uniformity of stock, sorts of burrs, the time between burrings, hour, power consumption, and life of the stone are described. Ezomatsu Todomatsu (Fir) were used mostly as pulping materials in the studies, was used too in part.In the next part, the best conditinn of manufacturing process and the optimum seasoning temperature of asplit which was used as joints between segments of vitrified artificial pulpstone are pointed out.The abstract are1.It has been proved possible to obtain 20-40% greater production of pulp per hour with the alundum stone than cement stone or natural stone. In fibre analysis, there is a considerable increase in the amount retained on the 20 mesh screen, and decrease of flour. The amount of rejects retained on the 65/1000″ screen plate is much comparatively, and freeness of stock is high in general, and strength of pulp test sheets is superior than cement stone, and inferior than natural stone.2. Uniformity of stock was observed by the variation of the highest and lowest values of freeness for nine days, and the rate of variation was alundum stone 85%, cement stone 90%, and natural stone 104%, therefore the most uniform stock is produced with the alundum stone in comparison with the rest.3. On the alundum stone 10 cut spiral burr, 10 point diamond burr, 14 point diamond burr, 2 cut spiral burr in connection with 12 point diamond burr were used, but the distinct conclusion could not derived, for at present burring is done by the help of sensibility of hand, and so the effect of intensity of burring is great. But it appears that 10 cut spiral burr or 2 cut spiral X 12 point diamond burr is suitable for the stone. The time between burrings are four to five days in the case of Ezomatsu (Spruce) and Todomatsu (Fir), and two days in Akamatsu (Pine).4. As has been previously mentioned, the production of pulp per hour increased, and moreover power consumption per100 pounds pulp production decreased.5. It is presumed that the life of thestone (stone diameter 54″, available dimensions in the radius 2′/2″) will be three years and four months in the case of Ezomatsu (Spruce) and Todomatsu (Fir).6. The combination rate of grit of the stone is 36 mesh-33%, 46 mesh-33%, 60 mesh-34%, hardness of the stone is 0, and structure of the stone is 8. The stoneissuitable for pine, and produces high quality pulp which has not much fibre bundles.7. Asplit was used as joints between segments of the stone, and Be 25-26 phenol resin is suitable for easy work.8. The finer alundum grit or silicate powder is used as the filler of phenol plastic, the stronger the tensile strength is and so fines past 150 mesh are desirable 9. As hardening catalysis, para-toluol sulpho-chloride (5%) which react slowly is suitable.10. In consideration of expansion of drum, segments and resin, it is desirable that temperature of seasoning is not too high, about 100°C.