A uniaxial creep test method using an ultra-miniature creep (Ultra-MC) specimen with a size equivalent to that of a small punch creep (SPC) specimen was developed in this study. It was confirmed that the devised Ultra-MC specimen had the self-alignment function and geometry optimized by FEM analysis. In addition, by comparing the creep test results of the Ultra-MC specimen with the standard specimen (ϕ6), the applicability of Ultra-MC testing method was confirmed. The creep rupture time of the Ultra-MC specimen was found to be good agreement with that of the standard specimen, and the deviation of the creep rupture time was small. On the other hand, the creep deformation of the Ultra-MC specimen was larger than that of the standard specimen. By FEM analysis, this was found to be due to the creep deformation in the shoulder portion of the Ultra-MC specimen. So, a modification procedure for adjusting the creep property of the Ultra-MC specimen to that of the standard specimen was proposed.
