A carbon nanohorn (CNH) is oxidized to make an opening in the side of the CNH. A substance to be included, e.g., a metal, is introduced through the opening. The inclusion substance is moved to a tip part of the carbon nanohorn through heat treatment in vacuum or an inert gas. The CNH is further heat treated in an atmosphere containing oxygen in a low concentration to remove the carbon layer in the tip through catalysis of the inclusion substance. This exposes the inclusion substance. If the inclusion substance is a metal which is not moved to a tip part by the heat treatment in vacuum or an inert gas, the carbon part surrounding the fine catalyst particle is specifically burned by a heat treatment in an low oxygen concentration atmosphere, while utilizing the catalysis. Thus, the fine catalyst particle is fixed to the tip part of the CNH.