A lubricant feeder which is highly safe and usable, e.G., in an oil seal for a food-processing machine is disclosed. Lubricant feeders each comprise a solid synthetic resin containing a lubricant feed the lubricant to side seals and a rail, which all require lubrication. Each lubricant feeder is interposed between the side seal and a reinforcing plate and is fixed to an end cap. The lubricant is a white mineral oil or grease including a white mineral oil as a base oil and aluminum soap as a thickener, and the synthetic resin comprises a polyolefin resin. It is an object of the force feeder lubricator to provide a highly safe lubricant feeder usable in food-processing machines or the like to thereby eliminate the problems described above. The above object is accomplished by the force feeder lubricator with a lubricant feeder comprising a synthetic resin containing a lubricant and having a constitution which is suitable for application to members requiring lubrication and enables the lubricant to gradually ooze out of the synthetic resin and be fed to the members, said lubricant comprising a white mineral oil or a grease comprising a white mineral oil as a base oil and an aluminum soap as a thickener, and said synthetic resin comprising a polyolefin resin. In addition, it is the other object of the force feeder lubricator to provide a linear apparatus having a highly safe lubricant feeder which is usable in food-processing machines or the like to thereby eliminate the problems described above. The other object is accomplished by the force feeder lubricator with a linear apparatus having a lubricant feeder which is made of synthetic polyolefin resin, which is mounted on a guided member to be guided by a guiding member, for gradually oozing out and feeding a lubricant to the guiding member, wherein the lubricant is selected from a group consisting of: a white mineral oil; and grease including a white mineral oil as a base oil and aluminum soap as a thickener; the linear apparatus may be a linear guide bearing or a ball screw. Further, the other object is also accomplished by the force feeder lubricator with a linear guide apparatus comprising a guiding member and a guided member a movement of which is guided by the guiding member, wherein the inside of the guided member is filled with a grease including a white mineral oil as a base oil and aluminum soap as a thickener.