The rates at which various knives are worn against the rubbers were measured at 25 ℃ and 100 ℃ using a new blade-type abrader, in which the frictional and normal forces could be monitored continuously during abrasion. The rate of wear of theknife was determined by measuring the worn width of the knife tip using a scanning electron microscopy. Natural rubber, polybutadiene rubber, styrene-butadiene rubber, and acrylonitrile-butadiene rubber were used to investigate the effect of rubber type on the wear rate of steel knife. In an attempt to understand the effect of material type of knife on the wear rate of knife, steel, tungsten carbide, TiN coated tungsten carbide, and zirconia were selected as the knife material. Worn surfaces of steel knife and zirconia knife were found to be relatively round and smooth, while that of tungsten carbide knife was rough. The rates of wear of steel knife varied more than 10 times depending on the rubber type. A zirconia knife was estimated to be the most resistant to wear byrubber. A tungsten carbide knife was much better than a steel knife, but slightly inferior to the zirconia knife.