NOVELTY - Surface-modified carbon material (I), where a value obtained by dividing a weight loss (% by mass) by a specific surface area (m2/g) of the carbon material is not more than 1.5x 10-3; and the weight loss is a value when the temperature is raised from 150 to 250 degrees C at a rate of 10 degrees C/minute in a nitrogen gas atmosphere having a purity of 99.99% or more, is new.    USE - (I) is useful in a catalyst-supported carbon material, which is useful in a membrane and electrode. The membrane and electrode are useful in a fuel cell (all claimed). (I) is useful as a pigment, a filler or a reinforcing agent in blending and producing a rubber compound for tire. (I) is useful as a noble metal catalyst carrier for chemical synthesis. The fuel cell is useful: for transportation (vehicles including passenger car, goods wagon, two-wheeled vehicle and personal vehicle), shipping and household (including a cogeneration system, a vacuum cleaner and a robot) and portable instrument (including a cellular phone, a laptop personal computer, an electronic still camera, PDA, a video camera and a portable video game player); for a potable power generator and an outdoor lighting device; as a power source of an industrial or household robot or other toys; and as a secondary battery or a power source for charging a capacitor.    ADVANTAGE - (I) has high heat stability and high durability. (I) imparts abrasion resistance and/or reduced hysteresis to the rubber compound containing it, hence a tire having a lower hysteresis value reduces the rolling resistance, hence it is able to reduce the fuel.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) the preparation of (I);    (2) a catalyst-supported carbon material comprising a surface-modified carbon material and a metal catalyst supported on it; and    (3) a membrane and electrode assembly (10) comprising a porous conductive sheet and a catalyst layer provided in contact with the porous conductive sheet, where the catalyst layer contains the catalyst-supported carbon material.    DESCRIPTION OF DRAWING(S) - The figure is a diagrammatic cross-sectional view showing a fuel cell comprising (I).    Membrane and electrode assembly (10)    Packagings (14)    Opening on anode side (15)    Opening on cathode side (16)    Collectors (17)    Separators. (21, 22)