pressure by hot pressing with a stroke compression ratio of 10 then a carbon preform having a fiber volume content vf of 60 vol and a bulk density of 1110 kg m 3 was obtained when this carbon preform was extracted from the die it maintained its shape completely when this carbon preform was subjected to a non destructive inspection by the x ray ct scanner and thereafter cutting inspection no internal defect e g a crack was observed a good preform was thus obtained when the thermal conductivity of this preform was measured at 25 u00b0 c in the direction of thickness it was 0 6 w m k the same pitch fibers as those of example 1 were filled in a cylindrical container under the completely same conditions as in example 1 at this time the fiber volume content vf and the bulk density of the pitch fibers filled in the container were 5 vol and 60 kg m 3 respectively while maintaining the shape as they were filled the pitch fibers were subjected to infusibilization in air together with the cylindrical container then while maintaining the shape as they were infusibilized the pitch fibers were transferred from the cylindrical container to a graphite cylindrical die for uniaxial pressing calcination and molding were performed at 1 000 u00b0 c for one hour under a uniaxial.