(Problem)In conventional method for producing artificial graphite, in order to obtain a product having excellent crystallinity, it was necessary to mold a filler and a binder and then repeat impregnation, carbonization and graphitization, and since carbonization and graphitization proceeded by a solid phase reaction, a period of time of as long as 2 to 3 months was required for the production and cost was high and further, a large size structure in the shape of column and cylinder could not be produced. In addition, nanocarbon materials such as carbon nanotube, carbon nanofiber and carbon nanohorn could not be produced.(Means to Solve)A properly pre-baked filler is sealed in a graphite vessel and is subsequently subjected to hot isostatic pressing (HIP) treatment, thereby allowing gases such as hydrocarbon and hydrogen to be generated from the filler and precipitating vapor-phase-grown graphite around and inside the filler using the generated gases as a source material, and thereby, an integrated structure of carbide of the filler and the vapor-phase-grown graphite is produced. In addition, nanocarbon materials are produced selectively and efficiently by adding a catalyst or adjusting the HIP treating temperature.