A set of load controlled fatigue tests of smooth and notched specimens was conducted in intermediate and high cycle fatigue ranges in order to re-evaluate the applicability of a predicting formula of fatigue strength reduction factor of crack initiation basis, that was proposed in a previous paper. Materials tested were electro-gas welded metal of a mild steel and base metals of 50kg/mm² class and 70kg/mm² class high strength steels. Notch geometries investigated ranged over elastic stress concentration factors of approximately 2.2 to 8.6. An FEM analysis of cyclic elasto-plastic strains distributed in the notched net section was also made and discussed in comparison with experimental results measured by strain gauges during a fatigue test. Results indicated that the fatigue strength reduction factor of crack initiation basis in high cycle range will become approximately 0.8 to 1.0 times as great as the elastic strees concentration factor of a notch. A formula presented in this paper will be available in estimating the fatigue strength reduction factor of crack initiation basis for any stress ratio. In case where the notch root may be subjected to cyclic yielding, the fatigue strength reduction factor is predicted by the proposed formula by applying the fatigue strength of smooth material for the stress ratio of -1. The application of the fatigue strength of smooth material for the stress ratio of zero will provide conservative estimation of the fatigue strength reduction factor.