To obtain a coating agent which is excellent in adhesion to rubber and has sliding properties and non-tackiness compatibly.

This coating agent comprises 100 pts. wt. of a wax having a particle diameter of 0.5-50 μm and a softening point of 60-100°C and 5-300 pts. wt.(as a solid component) of a polyester adhesive having a softening point of 120-180°C and a glass transition temperature Tg of -10 to 100°C and/or an acid-modified polyethylene resin having a softening point of 90-140°C and a molecular weight of 1,000-8,000. The coating agent may comprise further 5-300 pts. wt. (as an oil component) of an emulsion type silicone oil having a viscosity of 10-10,000 mPa×s and/or 0.1-50 pts. wt. of an isocyanate compound. When the isocyanate compound is used together, dynamic and static friction coefficients of a film of the coating agent formed there can further be decreased.