PURPOSE: To improve the adhesion between a spring steel and an electrodeposition painting film and to provide a rust preventive treatment method for spring steel which can provide high corrosion resistance by shotting the powder and granules of zinc to the surface of the spring steel subjected to shot peening.

CONSTITUTION: Fine glass beads, etc. are striken against the surface of a spring steel by utilizing compressed air to remove the oxide film layer of the surface and to increase the hardness on the surface layer of the spring steel (treatment A). Zinc powder and granules having about 5W1,500μ are then striken directly or together with fine granules such as glass beads to the surface of the spring steel removed of the oxide film by utilizing compressed air, etc. to form 3W20μ zinc film layer on the surface of the spring steel (treatment B). A zinc phosphate film layer is then formed on the zinc film at 1.0W10.0g/cm2 (treatment C). An electrodeposition painting film is formed at 10W40μ on the surface of the spring steel formed with the zinc phosphate film layer by a method of dipping the steel in an electrodeposition paint of an anion type or the like (treatment D) by which the intended rust preventive treatment is completed.