Generally speaking, it is difficult to evaluate the degradation of components using destructive techniques, because conventional uniaxial creep specimens were sometimes too large to collect them from local area of target components. Miniature Creep (MC) tests have been recognized as a semi-destructive technique. They employ small specimens that can reduce the conventional uniaxial creep specimen in similarity. In this study, MC tests of 2mm in diameter were performed in Argon gas to measure creep properties, and compared them with uniaxial creep test results employing 2.25Cr-1Mo steel. It was shown that MC rupture lives were a bit shorter than those of uniaxial creep due to some oxidation and some addition of bending stress to nominal stress.