The authors proposed one technique for reduction of stress concentration at stop hole edges which is closing the crack surface between stop holes by using ICR treatment. To evaluate the effectiveness of proposed method, bending fatigue tests of stop hole with ICR treatment were carried out. As the results of bending fatigue tests, fatigue strength of stop hole with ICR treatment was 3 times higher than that without ICR treatment. Additionally, to estimate fatigue strength of stop hole with ICR treatment, estimated equation of stress range of stop hole with ICR treatment was proposed. Fatigue life can be accurately estimated by using the proposed equation.