cap 4 the nose part 25 is integral with the basal part 26 and exposed at an end face 34 thereof to the slot 32 in the turnaround passage 30 the porous compact of the lubricant reservoir main body 22 has a molded density less in the porous compact of the applicator nose 23 with the linear motion guide unit constructed as stated earlier thus as the lubricant soaked in the applicator nose 23 is consumed the lubricant previously held in the lubricant reservoir main body 22 may move to be resupplied into the applicator nose 23 with the capillary action the porous compact to provide the lubricant reservoir plate 21 is made of finely powdery ultrahigh molecular weight synthetic resin which is first subjected to compacting and the resulting compact is subsequently sintered at elevated temperature in the sintered compact the fine particles of the powdery synthetic resin partially coalesce with each other with leaving intercommunicating voids to provide open porous or open cellular texture whose pores or cells preserved among fine particles are open each other through interstices or channels the sintered resinous material of the lubricant reservoir main body 22 has a molded density less than 0 60 g cm 3 u02dc 0 70 g cm 3 and the sintered resinous material of the applicator nose has a molded density in the range of from 0 60 g cm 3 to 0 70 g cm.