Conventional porous carbon materials obtained by carbonizing an organic gel were prone to shrinkage during their manufacture, in the course of which the density rose and the specific surface area decreased. Another problem was that density and specific surface area were difficult to control after an organic gel had already been formed. In the present invention, a carbon material with a large specific surface area is formed by forming a composite porous material having a reticulated skeleton and composed of a dry gel of an inorganic oxide, and taking advantage of the reaction of this dry gel of an inorganic oxide as a structural support. In one method, a carbon material is formed in this reticulated skeleton in a state in which the characteristics of a dry gel of an inorganic oxide with a large specific surface area are maintained. In another method, the specific surface area of a carbon material is further increased by removing the inorganic oxide of the reticulated skeleton in which the carbon material was formed.