Nanoporous platinum, silica, and titania have been made using activated carbon templates in a supercritical solvent. Precursors were dissolved in supercritical carbon dioxide and attached to an activated carbon template. After the activated carbon in the sample coated with materials was removed by calcination or oxygen plasma treatment, samples faithfully that replicated not only macroscopic shape (e.g., fiber, powder, granule) but also porous structure on the nanometer scale were obtained. In addition, we confirmed that such a faithful reflection in the nanoscale structure is realized only by use of a supercritical fluid as a solvent, in comparison with impregnation in a liquid.