The turbine roller bearings of a turbojet-engine operate under the severe condition of high speed, high temperature and heavy load. Therefore, there are many problems in practical use. The object of this experiment is to obtain the fundamental data on whether oil-mist lubrication is applicable in practical use or not. Experiments are carried out under various severe conditions of speeds, temperatures and loads. Performances by oil-mist lubrication are also compared with those by oil-jet lubrication. As the result of experiments, the rise of bearing temperature is found to be a function of rotating speed and air quantity, independent of oil quantity and load. It is understood that the air in oilmist lubrication acts an important role of cooling medium. The cooling effect by oil-mist lubrication is very large and in this point oil-mist lubrication is better than oil-jet lubrication.