The invention provides a non-black, cheap and easily available lubricating coating material having calcium sulfate as a base and having superior lubricating performances as a solid lubricant. A sufficient quantity of organic lubricant and solid lubricant can sustain uniform functionality even microscopically even while being made into a thin film by means of coating and surface expansion of a steel material in plastic working. The solid lubricant is characterized in that the solid lubricant is prepared by precipitation of the calcium salt of a fatty acid on the surface of calcium sulfate crystals.