A lubricant feeder which is highly safe and usable, e.g., in an oil seal for a food-processing machine is disclosed. Lubricant feeders 11 each comprising a solid synthetic resin containing a lubricant feed the lubricant to side seals 10 and a rail 1, which all require lubrication. Each lubricant feeder 11 is interposed between the side seal 10 and a reinforcing plate 20 and is fixed to an end cap 2B. The lubricant is a white mineral oil or a grease including a white mineral oil as a base oil and aluminum soap as a thickener, and the synthetic resin comprises a polyolefin resin.