It is essential to improve a traction coefficient which gives influence to all performance under actual operating conditions in order to apply a toroidal CVT incorporating a traction drive system to automobiles. The first report describes important parameters of the micro-surface structure of the circumferential grooves for improving the traction coefficient while assuring high durability at the same time. Furthermore, this paper describes an attempt which tries to improve traction coefficient of an actual CVT variator by using a optimized circumferential grooves. The test result proves that a traction coefficient can be improved by optimizing surface texture without spoiling durability.