PURPOSE: To prevent leakage of the grease by changing a crystal of the thickener into fine particles and mixing them in the semi-solid grease, and performing homogenization processing, and impregnating narrow holes of a porous sliding bearing with the grease, and thereafter, heating it at a temperature more than a phase change temperature of the grease and cooling it.

CONSTITUTION: In a grease manufacturing process 1, a mixing process 6 for mixing the thickener and the additive, a heating and melting process 7 for heating the grease at a temperature more than a phase change temperature thereof for melting, and a cooling process 8 are performed to the basic oil in order. Thereafter, through a homogenization processing process 2, a sintered bearing located in a container is impregnated with the grease in a vacuum impregnation process 3, and the bearing is heated again at a temperature more than a phase change temperature of the grease, and next, it is cooled to be produced. Consequently, an apparent viscosity of the grease is raised to prevent the leakage, and the stabilized lubricated condition can be maintained for a long time.