Microvalves are the essential parts of valveless micropumps and other integrated microfiudic systems. The non moving parts (NMP) valve of which geometry is fixed is a simple and reliable valving concept. This paper proposes R type valve as the improved form of 'Tesla valve' which is one of the NMP valves, and evaluated its performance numerically. In the R type valve case, diodicity was 1.37 at Re = 500 and 14% more efficient than the optimized Tesla valve. In addition, the flow characteristics of pulsating flow in low Re regime was different from those of steady flow with the identical instantaneous Re conditions.