Since traction drives need high contact force to transmit power, high contact pressures arise at the points of contact between rollers. These pressures cause failure through rolling contact fatigue. Therefore, prediction of the rolling contact fatigue strength is essential during the design of a traction drive. If clean steels with reduced density of inclusions in materials is used, there is a possibility that the improvement of rolling contact fatigue strength and decrease of the scatter of strength. In this study, the rolling contact fatigue strength and scatter of clean steel rollers were evaluated by experiment. As a result of experiment, the rolling contact fatigue strength was 1156.2 MPa and the standard deviation was 15.4 MPa. In case of ordinary steels, the rolling contact fatigue strength was 1008.7MPa and the standard deviation was 85.0 MPa. From this fact, the rolling contact fatigue strength for 107 cycles improved by 14.6% and the standard deviation was decreased by 69.6 MPa when clean steel was used.