In this study, we've used carburized-quenched-tempered steels that received shot-peening process with different shot grain sizes and evaluated variation of surface property of the steels. As a result of study, it is demonstrated that the fatigue life of carburized steels can be prolonged significantly by increasing surface hardness and compressive residual stress and by reducing surface roughness and abnormal carburized case depth at superficial layer, which we've investigated in the study.