▎ 摘　　要

NOVELTY - Graphene material having a total porosity of 60% or more and an open porosity of 50% or more. USE - The graphene is used in a substrate for sustained release of a non-aqueous component (claimed). ADVANTAGE - The graphene material is lightweight and has large retention capacity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) (1) a method for producing a graphene material, involving (I-1) heat-treating thermally expandable graphite to obtain thermally expandable graphite, (I-2) pressure-molding the thermally expandable graphite to obtain a pressure-molded body, and (I-3) subjecting the pressure-molded body to open-pore processing by heating to obtain a graphene material; and (2) (2) a method for producing thermally expandable graphite, involving (a) a step of preparing a vertically erected tube surrounded by a heater and having its interior heated by the heater, (b) continuously supplying thermally expandable graphite from the lower end of the tube into the tube in an airflow, (c) heat-treating the thermally expandable graphite while the thermally expandable graphite passes through the tube from bottom to top in an air current to convert it into thermally expandable graphite, and (d) continuously obtaining the thermally expandable graphite from the upper end of the tube.