PURPOSE: To improve the reliability of bolt fastening by markedly decreasing a change in the coefficient of sliding friction due to a change in the temperature of the air in fastening a member or the like, by adding a specified amount of tetrafluoroethylene as a lubricant to a primary rust-preventive paint for a high tensile bolt or the like.

CONSTITUTION: 1W3% tetrafluoroethylene as a lubricant is added to a primary rust-preventive paint for a high tensile bolt, etc., used in fastening a member. The reliability of bolt fastening can be markedly improved because the paint can retain lubricity and can markedly decreased in a change in the coefficient of sliding friction of the bolt coated with this paint due to a change in the temperature of the air.