1. A method for setting a shape and working stress of a steel member comprising the steps of finding the relationship between a maximum value of diffusible hydrogen contents of unfailed specimens (H c ) and Weibull stress and finding a content of diffusible hydrogen entered into steel from the environment due to corrosion during use of the steel member (H e ); finding Weibull stress in the H c which is equal to the H e ; and determining a shape and working stress of the steel member so as to provide stress below the Weibull stress.