A simplified version of the cyclic resistance-curve-method for predicting the fatigue thresholds of pre-cracked components under mean stresses was proposed. The method requires one material data such as the hardness or the tensile strength for prediction. The relation between the Stage I nonpropagating crack length and the stress amplitude was unique irrespective of the stress ratio. The length of the Stage I cracks was given as a function of the applied stress and the Vicker's hardness. The fatigue limit of smooth specimens and pre-cracked specimens could be predicted from the hardness under arbitrary mean stresses by using the simplified cyclic resistance-curve-method. The fatigue limit predicted by the simplified method was larger than that by the original resistance-curvemethod. The predicted values of the fatigue limit for crack extension, the fatigue limit for fracture, and the length of non-propagating cracks agreed very wall with the experimental results.