To obtain a better understanding of high temperature creep deformation, high temperature short time creep tests have been done in vacuum (∼10−5 mmHg) on high purity nickel, OFHC copper and 20% Cr-30% Ni low carbon austenitic steel. By continuously observing surface structures revealed by thermal etching during a test with an optical microscope, investigation was made on how the microstructural change during deformation could be made clear from the results and the following conclusions were obtained. (1) In the cases of nickel crept at 850, 900 and 950°C under stresses of 1.0∼2.0 kg/mm2, OFHC copper at 800, 850 and 900°C under stresses of 0.3∼0.9 kg/mm2 and austenitic steel at the same temperatures as in OFHC copper under stresses of 1.0∼3.5 kg/mm2, subboundaries start to form at the very early stage of transient creep. They gradually develop inside grains and then form subgrains at the end of transient creep. Subgrains thus formed do not change their shape during steady state creep. (2) Characters of subgrains formed in every specimen are greatly affected by stress rather than temperature. That is, the higher is the stress the finer is the structure, and there also is a tendency to change its shape from polygonal to rectangular. (3) In pure nickel when temperature is high and stress is low, recrystallization is easy to occur in some areas inside a grain during creep. On the other hand, in OFHC copper and austenitic steel, coarse facetings are formed in a considerable number of grains; in some grains they cover the area. (4) Grain boundaries and subboundaries can be observed because of grooving along them. But in the area where coarse faceting are observed, subboundaries are quite difficult to be observed. (5) By comparing etch pit structures, deformation structures in the surface layer and inside a specimen are concluded to be the same.