Recently, because the micro-machine is noticed and electronic equipments are made much lighter and smaller, the demand for micro materials is increasing. The research which investigates the mechanical property of micro materials have been carried out. However the mechanical properties data of the micro materials obviously run short and the evaluation method of micro materials is different according to the researcher. Therefore, the establishment of the test method for the micro materials is very necessary. In this study, SUS304 thin sheets with thicknesses of 10μm and 20μm were used. Specimens were manufactured using electro-spark machining. Afterwards, the machined surface was polished. The fatigue tests were carried out using these specimens. As the results, it was seen that variation in fatigue lives of specimen with thickness of 10μm was larger than that with thickness of 20μm.
