The present invention provides a lubrication system that improves the force of retaining a lubricating component of a foamed lubricant, is capable of minimizing the amount of exudation of the lubricating component which occurs owing to deformation of the foamed lubricant, is capable of compensating for a lubricating function even when the lubricating component exudes insufficiently from the foamed lubricant, and is capable of complying with a demand that the lubrication system has a long life and can be produced at a low cost. The lubrication system comprises a foamed lubricant containing a lubricating component in a resin thereof which foams, hardens, and becomes porous and a grease for auxiliary lubrication which is present together with the foamed lubricant in a portion to be lubricated. The grease for auxiliary lubrication satisfies a condition that (1) a penetration thereof is not less than 175 and less than 285 or that (2) a mixing ratio of a thickener to the grease for auxiliary lubrication is not less than 10 wt % and less than 40 wt %. As shown in the drawings, a foamed lubricant (9) and a grease (10) for auxiliary lubrication are present together inside a universal joint.