In this paper, the procedure which can estimate creep exponent and coefficient in Norton's law of the miniature sample from the impression size rather than the penetration depth is discussed based upon a high-temperature creep indentation test. First, an analytical solution related to the change in the impression size with dwelling time at an indentation load is solved by using a well-known problem of infinite creeping media embedding spherical cavity subjected to an inner pressure which characterizes an indentation load. The applicability of the formula to elastic–plastic-creeping model resembling an actual response is checked by conducting a nonlinear finite-element analysis combined with contact option. Finally, creep indentation tests are conducted for a high-Cr ferritic heat-resisting steel, grade 122. It is shown that the creep parameters at a lower stress level can be estimated at temperature 873 K.