A solid lubricant for bearings which is less likely to be washed away by water or liquid mud coming into bearings, and which can restrain the development of rust even in a harsh environment where high-concentration salt water comes into the bearings. A rust preventive in the form of a sulfonate or a fatty polyhydric alcohol partial ester is added to a composition made up of 5-97% by weight of a lubricating grease, 93-1% by weight of an ultra-high-molecular-weight polyolefin powder, and 1-50% by weight of oil exudation inhibitor, and mixed together. The mixture is then heated to a temperature higher than the gel point of the ultra-high-molecular-weight polyolefin and preferably lower than the dropping point of the lubricating grease and molded into the solid lubricant for bearings.