This study deals with the combination machining for creation of modified surface layer having superior roughness in metal processing. The combination machining is combined burnishing and finish cutting process. The modified surface layer which has high hardness and compressive residual stress is generated in the burnishing process, and the finish cutting of the small depth of cut is performed for obtaining the superior surface as a second process. The modified surface layer which has different metallographic structure from base material is observed by burnishing process, and its thickness is approximately 0.1mm. The characteristics and thickness of modified surface layer in burnishing process is mainly influenced the thrust force P, and the hardness and compressive residual stress of the surface layer are approximately HV500 and -400MPa in P=60N, though the surface roughness is inferior. In the finish cutting process, the depth of cut is set smaller than the thickness of modified surface layer generated in burnishing process. The residual stress of surface layer after finish cutting remains approximately -300MPa and the surface roughness of it do not differ from machined surface which is not burnished.
