To increase the fatigue limit of the automobile parts, especially, the following two items need to be improved: 1) Increase hardness near surface. 2) Introduce highly compressive residual stress near surface. Shot peening is useful technique to improve above items, economically. However, there are few studied evaluated the influences of shot peening method on the rotating bending fatigue limit, systematically. Therefore, the authors conducted a study by using carburized specimen treated four shot peening methods, and analyzed the correlation between the fatigue limit and the sum of yield stress(σ_Y) and maximum compressive residual stress(σ_rmax). As the result, the fatigue limit was given with an equation as follows:σ_W=0.3891(σ_Y+σ_rmax)