We observed that the lubrication effect is greater than the cooling effect for decreasing the friction heat in face grinding. It was clarified that cool-air grinding is difficult to apply to face grinding under the present grinding conditions. We could obtain the minimum ground surface roughness (hereafter noted as surface roughness) at a mist suppｌy volume of 15 to 30ml/h in mist grinding. The largest stock removal rate (hereafter noted as grinding efficiency) is obtained in mist grinding. However, grinding efficient was small in cool-air mist grinding, by which a large cooling effect of cool air was expected. Though mist and cool-air mist grinding perform similar to wet grinding in few grinding passes, wet grinding is properly applied by large chip removal action in many grinding passes.